RedM won't start - Not allowed for this game type

Description:
RedM fails during Rockstar entitlement validation with a 403 error “Not allowed for this game type”, even though Red Dead Redemption 2 (Steam version) and Red Dead Online both launch and work fine directly via Steam and via the Rockstar Games Launcher. RedM worked correctly on this same account roughly a year ago and stopped working since. Already tried a full clean reinstall of RedM and a full reinstall of the Rockstar Games Launcher —

issue persists.

Server artifact version:
Latest (client update was triggered automatically at launch before the error appeared)

Expected behavior:
RedM should pass Rockstar entitlement validation and proceed to the server browser, as it did previously on this same account/PC.

Current behavior:
RedM gets stuck at “VALIDATING ROCKSTAR ENTITLEMENTS” and shows a popup: “Authentication error — Not allowed for this game type.” The launcher correctly detects the Steam installation and successfully authenticates with the Rockstar Games Launcher (MTL), but the request to CPR (Rockstar cloud) is rejected with a 403.

Extra information:

  1. Game and Red Dead Online launch normally both via Steam directly and via Rockstar Games Launcher
  2. Steps already tried: full RedM reinstall, full Rockstar Games Launcher reinstall, clearing RedM cache, verifying Steam game file integrity, disabling VPN
  3. Issue reproduces consistently, including after full system reboot