connection test successful - login fail

Hello, there is a user in my company, that connection test was successful, while login failed.
How can I check reason, troubleshooting for him?
Thanks.

Environment: ASG RD 2018, SQL server 2016
Users are organized in AD group, authorization is set on Database permission.



  env config.png (Size: 52.5 KB / Downloads: 2)

  connection check.png (Size: 52.74 KB / Downloads: 2)

  before login.png (Size: 31.31 KB / Downloads: 3)

  login fail.png (Size: 35.85 KB / Downloads: 3)