Trunk intercluster_480 temporarily unavailable

[Rima]

Hello Team,

We have tow cucm v 11.5 and a trunk intercluster configured between them. We are facing an issue when trying to make a call between tow ip phones (oe registred on CUCM 1 & the other registred on CUCM2). On RTMT , we got the message sip2.0 480 temporarily unavailable 

Any kind of help would be greatly appreciated.

[TechLvr]

Have you tried resetting the trunks on both sides? 

[Nithin Eluvathingal]

I hope there is no recahbility issues between these two CUCM.  Check the firewall if there exist anything in between the traffic. Firewall inspections must be disabled  if any.