I'm trying your company's free edition of Veeam Backup & Replication. During the installation, I have problem login to my local SQLEXPRESS though I'm sure the windows account name used can login to the SQLEXPRESS db without problem. The error message I got is:
"The login is from an untrusted domain and cannot be used with Windows authentication."
As I'm not familiar with the system administration part, I can't grasp the idea of this error message. On the internet, people just say you need to change your code to use the SQL account, or add something in the computer ODBC. I guess none of them is of option to me.
Looks like the user account you specify has expired. Can you please confirm that you can connect via SQL Management Studio to the SQL Server Instance on this machine using the same credentials?
I just checked the user account(windows authentication) and I'm totally okay to login to my local SQLEXPRESS instance in MS SQL Server Management Studio. Do you need any other info or log file that may help to identify the login problem root cause?
If you're able to use the same account via SQL Management Studio installed on the backup server, then I would recommend contacting our technical team directly for the assistance with logs review.