There are two servers: db1 and db2. They are remote to us and I'm sure a firewall is involved. They also use a domain and windows authentication for us to connect to. We also have an account that the web server uses, we can also try to connect with (username/password). Several of us users are able to connect and work normally with db2. However, all of us are having connection issues with db1.
It's intermittent, though:
Sometimes I can connect to db1 and run a query (using Windows Authentication), or use the SQL Server Management Studio and explore the databases, but other times it hangs and I get the error (in the title). It may switch within seconds. When it does retrieve data, it is fast and doesn't skip like it would with packet loss. (I do not believe packet loss is the issue here.)
To db1, I can never connect using the username/password, however the web server always can. I can always connect both ways to db2 without issue.
The database administrator verifies that other people are able to connect OK, and that our accounts are not blocked or locked. He can see in the logs where we attempt to connect (by our IP). He says it does not appear to be anything on his end. We think there is nothing that is on our end (since we can connect to db2 just fine, which is essentially in the same location).
What could be causing this? Some closed obscure port on a firewall?