I have Yealink W60P that is working perfectly.
They have already been upgraded to the versions mentioned above. Was the first thing I did when I received the units .
Have you checked the router for SIP ALG? which provider are you using? ISP and Last mile provider?
My Afrihost Fibre was installed today, and it is no longer doing it after changing over to DHCP from PPPOE
Thank you for your assistance.
Perfect, please let us know if you need anything else.
Have a great day!