Hi,
Thank you for posting in Microsoft Q&A forum.
1,We can add the log on account in the SQL logins to have a try. Open SSMS and connect to the site database, then navigate to <Server>/Security/Logins, check if the computer account is there. If not, add it. If yes, remove it and add it back with the same setting. Then check the results.
2,We can also try to use a domian admin accout in the log on accout to have a try.
3,Please check the event log under Windows logs\Applicaiton to see if there is any further information about the login failure.
Similar threads for your reference:
SCCM Configuration Manager console cannot connect to Site
SQL Server startup errors on a standalone server
Thanks for your time. Have a nice day!
Best regards,
Simon
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