When your character is linked to a Steam Group and you join a multiplayer server, the server verifies with Steam that you are actually a member of that group. This prevents cheaters from pretending they are part of your group.
From what we've observed, Steam's September 27, 2026 maintenance appears to have restricted the ability to verify group membership for private profiles. This means verification is currently impossible for players with private profiles.
This could be an intentional change, but we've submitted a ticket to Steam Support asking for clarification. Currently, the relevant API (ISteamGameServer::RequestUserGroupStatus) documentation doesn't mention this restriction, despite group verification having worked for private profiles for many years.
Workarounds
Until we have further news, two options are:
- Create a per-server group from the in-game Information > Groups tab.
- Set your Steam profile to public. (Not really an option if you need to keep your profile private, sorry!)