Failed to connect to the specified server

[JamesJudge]

After restoring a SQL database I cannot connect to the restored DB from ArcCatlog 10.4.1 I am receiving this error message

Failed to connect to the specified server. Do you want to continue? Operation Failed

I've tried connecting as OSA and Database user. Also with SQL manager I have compared that the restored DB has the same uses and roles as our existing databases.

[George_Thompson · Accepted solution]

Did you change the name when you restored the DB? 

No matter which of the methods you use to move your SQL Server database, you cannot rename the database. When you restore a database, for example, you are given the opportunity to restore it with a different name. Don't do this with a geodatabase; you won't be able to connect to it.

Methods to move a geodatabase in SQL Server—Help | ArcGIS Desktop 

[JamesJudge]

Thank you

[TinaMorgan1]

This thread is a bit older, but wanted to add a tid bit from a case I just got.  

If you happen to rename the database in SQL Server, and do not remember the original geodatabase name, you can check that in the database_name column of your sde_table_registry table.  That table hard codes the name of the database as it was when the geodatabase was created.