Cannot connect to Leo AI in browser

Every time I try to use Brave Leo, I get the following message:
There was a network issue connecting to Leo, check your connection and try again.
Everything else works fine, both in the Brave browser and in the system overall.
Brave browser version: 1.77.101 Chromium: 135.0.7049.115 (Official Build) (64-bit)
Operating system: Linux Debian Testing, located in Russia.
I have tried both a direct connection and using a VPN (with an exit node in Switzerland).
What information do I need to provide to help localize the problem?

Hello - You may be affected by regional limitations. https://support.brave.com/hc/en-us/articles/34271483229581-Unavailable-Jurisdictions-for-Brave-Services