2Talk mailbox is not accessible using my house phone, *55 not recognised.

It is almost as if there is no outgoing DTMF tone.

On fibre, Skinny HG659 with Bigpipe firmware.

Using basic sip settings on HG659 found on 2Talk.

Incoming and outgoing calls ok.

I can access my voice mailbox using my cell phone, so I know voice messages are being stored.

Anyone come across this and know a fix for this?

TIA