There may be a configuration or setting specific to the new account that is causing the problem.
Verify that the new user account has the necessary attributes configured correctly. Specifically, check if the user's account properties are set up properly, including the User Logon Name and User Principal Name (UPN).
Confirm that the account is a member of the correct security groups with the necessary permissions for network access. Compare the group memberships of the A2 account with those of other working accounts.