We lost our server connection and I selected "Work Offline."
Vault folders were blue.
When the connection was restored, I had a heck of a time figuring out how to get online again.
Logging in did not do it. Folders were still blue.
I had to use the "Work On-line" option in the "Tools" tab (as shown below).
This seems a non-intuitive and obscure way for users to get online again, or am I missing something more basic and obvious?