Your error is probably one of your own making, probably unbeknownst to you too. “Trying to call UOBject:BeginDestroy from outside of UOBJect:ConditionalBeginDestroy on object None. Please fix up the calling code.”
Your mod was cooked with a reference to a file outside of the mod directory. This will always crash servers and clients if this occurs. The most common cause is the GameMode was not changed before cooking.
-WM