Managed to fix it. I deleted the t5 and demonware folder from AppData\Local\Plutonium\storage and successfully connected afterwards.

Dss0 Console returns “Com_ERROR: EXE_ERR_SERVER_TIMEOUT” if it helps.
I will try the non-steam version to see if it works.

Dss0 https://www.youtube.com/watch?v=W2zzNxsSero

Did a fresh install with steam and then downloaded the dlc from the link. Error still persists but apparently, it’s not about the dlc. The servers that I connect to and those I can’t seem to be random. I can’t find a pattern. Doesn’t matter if its base game or dlc. Game mode doesn’t seem to matter either.

I only installed the multiplayer portion. So only zombies and single player should be missing.

I have the same issue. I own base game and rezzurection on steam but cant join any dlc server.