Valheim Server Won't Start – Dedicated, Mods & Port 2456
Valheim dedicated server won't start? Port 2456–2458 UDP, BepInEx/mods, world backup & SteamCMD – Valheim troubleshooting.
Quick answer: Valheim won't start: open ports 2456–2458 UDP, check world backup and SteamCMD validate after updates.
If you landed here: Valheim dedicated crashes on start, world won't load or server restart loops.