You need a good connection for VPN. Usually, it goes down when someone in the office is streaming a movie, but could be a number of other reasons related to a network getting busier. One of the solution is to use Remote Access to a computer in the other office and use FileMaker from there.
Also a good way to connect. I often have the "pipe" clogged on my side (my neighbors kids, I suspect) and VPN or Remote Access can be flaky.
Be careful what you view
If you try to open a dense report, with calculations and summaries, FileMaker will appear to freeze, because there is so much data to load, and back and forth client server chatter. If you wait long enough ( a few minutes ), FileMaker should respond
Also, PING your server, to check the latency
> We do use often a VPN dial-in to connect into the company lan and use a FM server hosted database, all in a Max environment. Quite often which means several time an hour Filemaker freezes