Make sure that the password for SQL Server doesn't have various "special characters" like:
... those things can mess up things within SQL itself.
That said ... also - check the SQL side (SQL) Event Log. You're looking for:
- The fact that "Your user is actually trying to log on". (that makes sure that youre at least talking to the right server / DB and knocking at the right door).
- Any error around failure for the user to authenticate (could be useful).
If you don't see ANYTHING on SQL Server, you might not be able to reach the server itself (weird things such as DNS causing you grief, for instance?).