The Forward All Calls feature has a fault in design.
When you enable "Forward All Calls" for User A who is getting the call, to send them to User B , it should still use the "Connecting To..." greeting that is assigned for User A.
But the system plays the "Connecting To..." greeting of User B.
That is wrong.
It should play User A "Connecting To" greeting so that we can record a custom message tell the incoming caller "You have called Jane Doe at extension 123. She is away so we are automatically forwarding you to John Smith at extension 456". This way your incoming caller is not getting someone answering that they do not expect and do not know. For our clients, that is pretty critical - counselling services clients want to know they are reaching the person they intend to, or understand who they are being directed to.
You cannot edit the User B recording to provide that information, because that would mean every caller to User B would get that Connecting To message, which is not correct for calls that were actually intended for User B.
The only way I have been able to resolve this issue is through this series of extra steps, and it should not need us to do it this way:
Under Call Handling - Working Hours
Use "Add a Coworker" and select another user.
Use the slider under "Active" to disable the original user's "My Desktop and Apps" as a destination that will ring when a call comes in.
Ensure the Coworker you added is set to at least 4 rings.
Also ensure you set the Voicemail to go to the Coworker extension if the call is missed (in both the Working Hours and After Working Hours sections).
Now edit the "Connecting To..." recording for the original user to state your information about their call is being automatically forwarded to someone else.
Now it will work and actually play that message, while then forwarding the call to the other staff person, and if that staff person missed the call, the voicemail will go to them anyway.