Hi, we have 3 FusionPBX servers cloned from each other, all have worked fine since 2015. About 1 year ago, I upgraded one of the servers to FS PBX. Everything's been great, but randomly calls just stopped working (only on FS PBX server, other 2 servers are still fine). Outbound beeps busy. IVR's will play the greeting until I press and ext and it beeps busy then. Inbound sounds fine and rings, but phones don't ring. All exts on 2 deskphones and Ringotel app are registered fine and show in registration status. Yesterday I updated FS PBX to the latest, but still the same issue