Cannot forward voicemail to Common Area desk phone

Hi all,

We've got a number of common area desk phones, and sometimes one gets voicemail intended for the other. The issue is we can't seem to forward these voicemails to other common area phones. 

When we listen to a voicemail and press 6 to forward it, we're prompted to enter the extension. When we enter the extension of a common area phone, we get the message "Your entry is invalid. Please try again."

This seems to happen with any common area extension, and when attempting to transfer from either a desk phone or a softphone. Voicemails are able to be transferred to Users or Call Queues with no issue.

Is this a restriction of common areas we're not aware of? I can't find any documentation on this specific issue.

Thanks!