Failed to connect to presentation

When opening the presentation workspace, a pop-up window appears with the message:
"Something went wrong. Please wait—we'll reconnect you when it's fixed."
Clearing cookies doesn't help. However, if I turn on a VPN, it works fine (the country is Russia).
The problem is that I don't have a VPN on my work computer due to company policy. And most of the time when I work on presentations, it is at the office. Currently, I have to create presentations after work on my home computer. This didn't use to happen before—everything worked perfectly.
