By default Music on Hold is supported via the IP Office, please review the Avaya Contact Center Select Solution Description guide, Avaya Contact Center Select supported features:
Feature: Music On Hold, Supported: Yes, Provider: IP Office
If Music on Hold is being supported by event Handler in the OD scripts then the Music on Hold must be disabled on the IP Office. Please note disabling this in the IP Office will result in only callers within ACCS will received Music On Hold, callers outside of ACCS will not receive the feature.
To disable Music On Hold in IP Office:
Remove HoldMusic.wav here:
In IPO Manager / File / Advanced / Embedded File management
Disk – system – primary
Filename: HoldMusic.wav