Erroneous user account

If you create a ńew user with an erroneous account and you are using Windows authentication, user cannot login and gets a message about access denial. The error is sometimes not obvious and consist in a missing or erroneous character.

After creating anew user you cannot change the account through the application interface. If you want to change the account, you can perform it by a direct update in the database - in the table Person in the table aspnet_Users. 

USE [Your_OG_database]
 GO

UPDATE [dbo].[Person]
   SET [Account] = 'CorrectDomain\CorrectAccount'
WHERE [Id] = Id of the user
 GO

USE [Your_OG_database]
GO

UPDATE [dbo].[aspnet_Users]
SET [UserName] = 'CorrectDomain\CorrectAccount'
   ,[LoweredUserName] = 'correctdomain\correctaccount'
WHERE [Id] = Id of the user
GO