P26T and Draytek IP PBX 2820

[Rainman7]

I am wondering if anyone can help me please.

Have a couple of Yealink P26T phones and attached them to a Draytek IP PBX 2820. Got the phones registered and working. When a voice mail message is left you get the relvant icon on the screen.

When you press the voice mail button to listen to the message it asks you for a login / phone number. This is where I am stumped. If you type in the extension number, it tries to dial itself. I setup the 2820 to use the display name as authentication. Then changed the display name to the extension number. Tried get my message and same error as before.

Any help would be gratefully appreciated.