Have been the same problem. Re add cameras, reload NVR not were crowned with success. After just activated Virtual Host in network settings TCP\IP section all ip cameras became available.
My IPC 4631C-A worked only in 12V power line. When I measure capacitor with a multimeter, capacity was about 140 uf. After changed 220uf capacitor in poe board it's have a new life on poe line supply. Maybe this will be help someone.