OK,thanks!
I found the problem； The custom defined module is not upgraded to 4.4.0。
There is too little exception information ：）
There is no change！
run *.HttpApi.Host:
There is no process associated with this object
rollback to 4.3.3 ,all going well.
run *.DbMigrator：
System.NullReferenceException HResult=0x80004003 Message=Object reference not set to an instance of an object. Source=Volo.Abp.Core StackTrace: at Volo.Abp.AbpApplicationWithInternalServiceProvider.Dispose()
My code is canceled, stack no message. stack = null.
I misread it. That's it。 thank you liangshiwei laotie!!!
Results still the same, login button cannot be clicked;
