[BLOCKER] Can't launch session, module validation failed

Same error here since today – exact same message:

LogValkyrie: Error: FlowStep_ResolveSessionCandidates(): Candidate module […] failed validation with error: [http_error_500:valkyrie-cook-api.prod.ucs.on.epicgames.com]

Tried:

  • New map
  • Validation fixes
  • Restarting UEFN and PC
  • Duplicating the project
    → Still broken

Please confirm if this is a backend issue. Would be great if someone from Epic could acknowledge this, seems a lot of people are running into it.