Recently I had an issue where MOH intermittently was not playing to callers in a UCCX Queue. The symptoms were not logical. MOH played ok to a PSTN caller who connected to a CTI Port that was later also used for another PSTN caller where MOH did not play.

After checking the Data Sync in the AppAdmin portal, I could see that the renaming of the MOH file caused the UCCX and CUCM to become out of sync. A Simple ‘Data Resync’ on the Data Synchronisation page resolved the MOH issues.