MyCompanyName.MyProjectName.IdentityServer project

when I ask api https://localhost:44301/connect/token at version 3.1.5 it will get error reporting:

Volo.Abp.AbpException
  HResult=0x80131500
  Message={"error":"invalid_client"}
  Source=Volo.Abp.IdentityModel
  StackTrace:
   at Volo.Abp.IdentityModel.IdentityModelAuthenticationService.<GetAccessTokenAsync>d__29.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

but at version 3.0.5 can't get this question!