Voice Learning Center
Voice Learning Center / Why am I unable to make outbound calls on my UC client?
Enabling Caller ID block (Hide my Number) on the Unified Communications client breaks the outbound calling functionality. Check your Hide my Number setting, located under More Call Options > Hide my Number. Disable the Caller ID block/Hide my Number.
If Caller ID Block is needed, use the block feature available for each user in the Voice Administration Portal.