• ABP Framework version: v4.4.3
• UI type: Angular
• DB provider: EF Core
• Tiered (MVC) or Identity Server Separated (Angular): yes
• Exception message and stack trace:

[10:19:45 INF] Executed action xxx.xxx.xxxxx.Application.AppUsers.AppUserAppService.ImportByExcelFile (xxx.xxx.xxxxx.Application) in 665.5593ms
[10:19:45 INF] Executed endpoint 'xxx.xxx.xxxxx.Application.AppUsers.AppUserAppService.ImportByExcelFile (xxx.xxx.xxxxx.Application)'
[10:19:45 DBG] Added 0 entity changes to the current audit log
[10:19:45 DBG] Added 0 entity changes to the current audit log
[10:19:45 ERR] An exception occurred in the database while saving changes for context type 'Volo.Abp.Identity.EntityFrameworkCore.IdentityDbContext'.
System.InvalidOperationException: A second operation was started on this context before a previous operation completed. This is usually caused by different threads concurrently using the same instance of DbContext. For more information on how to avoid threading issues with DbContext, see

https://go.microsoft.com/fwlink/?linkid=2097913.
at Microsoft.EntityFrameworkCore.Internal.ConcurrencyDetector.EnterCriticalSection()
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(IList1 entriesToSave, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(DbContext _, Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) Unhandled exception. at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func4 operation, Func4 verifySucceeded, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) System.InvalidOperationException: A second operation was started on this context before a previous operation completed. This is usually caused by different threads concurrently using the same instance of DbContext. For more information on how to avoid threading issues with DbContext, see https://go.microsoft.com/fwlink/?linkid=2097913. at Microsoft.EntityFrameworkCore.Internal.ConcurrencyDetector.EnterCriticalSection() at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(IList1 entriesToSave, CancellationToken cancellationToken)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(DbContext _, Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)
at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func4 operation, Func4 verifySucceeded, CancellationToken cancellationToken)
at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)
at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)
[10:19:45 WRN] An exception occurred, but response has already started!
[10:19:45 ERR] An unhandled exception has occurred while executing the request.
System.InvalidOperationException: A second operation was started on this context before a previous operation completed. This is usually caused by different threads concurrently using the same instance of DbContext. For more information on how to avoid threading issues with DbContext, see https://go.microsoft.com/fwlink/?linkid=2097913.
at Microsoft.EntityFrameworkCore.Internal.ConcurrencyDetector.EnterCriticalSection()
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(IList1 entriesToSave, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(DbContext _, Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func4 operation, Func4 verifySucceeded, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) at Volo.Abp.EntityFrameworkCore.AbpDbContext1.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)
at Volo.Abp.Uow.UnitOfWork.SaveChangesAsync(CancellationToken cancellationToken)
System.ObjectDisposedException: Cannot access a disposed context instance. A common cause of this error is disposing a context instance that was resolved from dependency injection and then later trying to use the same context instance elsewhere in your application. This may occur if you are calling 'Dispose' on the context instance, or wrapping it in a using statement. If you are using dependency injection, you should let the dependency injection container take care of disposing context instances.
Object name: 'IdentityDbContext'.
at Microsoft.EntityFrameworkCore.DbContext.CheckDisposed()
at Microsoft.EntityFrameworkCore.DbContext.get_InternalServiceProvider()
at Microsoft.EntityFrameworkCore.DbContext.get_ChangeTracker()
at Volo.Abp.EntityFrameworkCore.AbpDbContext1.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) at Volo.Abp.Domain.Repositories.EntityFrameworkCore.EfCoreRepository2.InsertAsync(TEntity entity, Boolean autoSave, CancellationToken cancellationToken)
at Castle.DynamicProxy.AsyncInterceptorBase.ProceedAsynchronous[TResult](IInvocation invocation, IInvocationProceedInfo proceedInfo)
at Volo.Abp.Castle.DynamicProxy.CastleAbpMethodInvocationAdapterWithReturnValue1.ProceedAsync() at Volo.Abp.Uow.UnitOfWorkInterceptor.InterceptAsync(IAbpMethodInvocation invocation) at Volo.Abp.Castle.DynamicProxy.CastleAsyncAbpInterceptorAdapter1.InterceptAsync[TResult](IInvocation invocation, IInvocationProceedInfo proceedInfo, Func3 proceed) at Volo.Abp.Identity.IdentityUserStore.CreateAsync(IdentityUser user, CancellationToken cancellationToken) at Microsoft.AspNetCore.Identity.UserManager1.CreateAsync(TUser user)
at Castle.DynamicProxy.AsyncInterceptorBase.ProceedAsynchronous[TResult](IInvocation invocation, IInvocationProceedInfo proceedInfo)
at Volo.Abp.Castle.DynamicProxy.CastleAbpMethodInvocationAdapterWithReturnValue1.ProceedAsync() at Volo.Abp.Uow.UnitOfWorkInterceptor.InterceptAsync(IAbpMethodInvocation invocation) at Volo.Abp.Castle.DynamicProxy.CastleAsyncAbpInterceptorAdapter1.InterceptAsync[TResult](IInvocation invocation, IInvocationProceedInfo proceedInfo, Func3 proceed) at Volo.Abp.Identity.IdentityUserManager.CreateAsync(IdentityUser user, String password, Boolean validatePassword) at Castle.DynamicProxy.AsyncInterceptorBase.ProceedAsynchronous[TResult](IInvocation invocation, IInvocationProceedInfo proceedInfo) at Volo.Abp.Castle.DynamicProxy.CastleAbpMethodInvocationAdapterWithReturnValue1.ProceedAsync()
at Volo.Abp.Uow.UnitOfWorkInterceptor.InterceptAsync(IAbpMethodInvocation invocation)
at Volo.Abp.Castle.DynamicProxy.CastleAsyncAbpInterceptorAdapter1.InterceptAsync[TResult](IInvocation invocation, IInvocationProceedInfo proceedInfo, Func3 proceed)
at xxx.xxx.xxxxx.Application.AppUsers.AppUserAppService.<>c__DisplayClass8_0.<b__1>d.MoveNext() in D:\UserData\z004bt9z\Projects\clean-order-online\aspnet-core\src\xxx.xxx.xxxxx.Application\AppUsers\AppUserAppService.cs:line 125
--- End of stack trace from previous location ---
at System.Threading.Tasks.Task.<>c.b__140_1(Object state)
at System.Threading.QueueUserWorkItemCallback.<>c.<.cctor>b__6_0(QueueUserWorkItemCallback quwi)
at System.Threading.ExecutionContext.RunForThreadPoolUnsafe[TState](ExecutionContext executionContext, Action`1 callback, TState& state)
at System.Threading.QueueUserWorkItemCallback.Execute()
at System.Threading.ThreadPoolWorkQueue.Dispatch() at Volo.Abp.AspNetCore.Auditing.AbpAuditingMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)

at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
at Microsoft.AspNetCore.Authorization.Policy.AuthorizationMiddlewareResultHandler.HandleAsync(RequestDelegate next, HttpContext context, AuthorizationPolicy policy, PolicyAuthorizationResult authorizeResult)
at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
at IdentityServer4.Hosting.IdentityServerMiddleware.Invoke(HttpContext context, IEndpointRouter router, IUserSession session, IEventService events, IBackChannelLogoutService backChannelLogoutService)
at IdentityServer4.Hosting.MutualTlsEndpointMiddleware.Invoke(HttpContext context, IAuthenticationSchemeProvider schemes)
at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
at IdentityServer4.Hosting.BaseUrlMiddleware.Invoke(HttpContext context)
at Volo.Abp.AspNetCore.Uow.AbpUnitOfWorkMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at Volo.Abp.AspNetCore.ExceptionHandling.AbpExceptionHandlingMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Volo.Abp.AspNetCore.ExceptionHandling.AbpExceptionHandlingMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at Volo.Abp.AspNetCore.MultiTenancy.MultiTenancyMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Builder.ApplicationBuilderAbpJwtTokenMiddlewareExtension.<>c__DisplayClass0_0.<b__0>d.MoveNext()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
at Volo.Abp.AspNetCore.Tracing.AbpCorrelationIdMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Localization.RequestLocalizationMiddleware.Invoke(HttpContext context)
at Microsoft.AspNetCore.RequestLocalization.AbpRequestLocalizationMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)
[10:19:45 WRN] The response has already started, the error page middleware will not be executed.
[10:19:45 ERR] Connection id "0HMG658PM8MSN", Request id "0HMG658PM8MSN:00000011": An unhandled exception was thrown by the application.
System.InvalidOperationException: A second operation was started on this context before a previous operation completed. This is usually caused by different threads concurrently using the same instance of DbContext. For more information on how to avoid threading issues with DbContext, see https://go.microsoft.com/fwlink/?linkid=2097913.
at Microsoft.EntityFrameworkCore.Internal.ConcurrencyDetector.EnterCriticalSection()
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(IList1 entriesToSave, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(DbContext _, Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func4 operation, Func4 verifySucceeded, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) at Volo.Abp.EntityFrameworkCore.AbpDbContext1.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)
at Volo.Abp.Uow.UnitOfWork.SaveChangesAsync(CancellationToken cancellationToken)
at Volo.Abp.AspNetCore.Auditing.AbpAuditingMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
at Microsoft.AspNetCore.Authorization.Policy.AuthorizationMiddlewareResultHandler.HandleAsync(RequestDelegate next, HttpContext context, AuthorizationPolicy policy, PolicyAuthorizationResult authorizeResult)
at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
at IdentityServer4.Hosting.IdentityServerMiddleware.Invoke(HttpContext context, IEndpointRouter router, IUserSession session, IEventService events, IBackChannelLogoutService backChannelLogoutService)
at IdentityServer4.Hosting.MutualTlsEndpointMiddleware.Invoke(HttpContext context, IAuthenticationSchemeProvider schemes)
at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
at IdentityServer4.Hosting.BaseUrlMiddleware.Invoke(HttpContext context)
at Volo.Abp.AspNetCore.Uow.AbpUnitOfWorkMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at Volo.Abp.AspNetCore.ExceptionHandling.AbpExceptionHandlingMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Volo.Abp.AspNetCore.ExceptionHandling.AbpExceptionHandlingMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at Volo.Abp.AspNetCore.MultiTenancy.MultiTenancyMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Builder.ApplicationBuilderAbpJwtTokenMiddlewareExtension.<>c__DisplayClass0_0.<b__0>d.MoveNext()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
at Volo.Abp.AspNetCore.Tracing.AbpCorrelationIdMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Localization.RequestLocalizationMiddleware.Invoke(HttpContext context)
at Microsoft.AspNetCore.RequestLocalization.AbpRequestLocalizationMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)
at Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserRefreshMiddleware.InvokeAsync(HttpContext context)
at Microsoft.AspNetCore.Builder.Extensions.MapWhenMiddleware.Invoke(HttpContext context)
at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ProcessRequests[TContext](IHttpApplication`1 application)
[10:19:45 INF] Request finished HTTP/2 POST https://localhost:44361/api/app/app-user/import-by-excel-file multipart/form-data;+boundary=----WebKitFormBoundaryY45VXuF5ieSssZyI 11975 - 200 - application/json;+charset=utf-8 770.7691ms

watch : Exited with error code -532462766
watch : Waiting for a file to change before restarting dotnet...

• Steps to reproduce the issue:"

[UnitOfWork]
public virtual async Task<ListResultDto<AppUserDto>> ImportByExcelFile(IFormFile file)
{
    ...
    await _identityUserManager.CreateAsync(ObjectMapper.Map<CreateUpdateAppUserDto, IdentityUser>(s), userPwd, false);
    ...
}