DFSR Event ID 5002: SYSVOL partners cannot hold an RPC session open
Event ID 5002 means DFSR lost its RPC session to a partner DC. Repair name resolution, firewall rules and the computer account, then restart DFSR.
Event ID 5002 and 5011: the WsusPool application pool keeps dying
Event ID 5002, 5011 and 5013 mean WsusPool crashed enough times to be disabled. Raise memory limits and prune the SUSDB to keep the pool alive.