The DVR issues a timeout. How to solve the problem?

Question

Mikrotik

Good afternoon!

There are 2 offices that are connected via the L2TP protocol, everything works well, I go to their devices and see everything. Most recently, I was sorting through the network, I noticed such a problem that he could not connect to the DVR from a neighboring office. Timeout error. If you log in through a local computer, which is also located at a remote office, everything shows fine.

Tried by enabling UPnP, as well as the LAN internal bridge, but unfortunately the situation has not changed. Where should you drip? Thank you!