We have just had our third customer now who has had a TP Link modem and had issues with their phones on Vital, but not our old system. Their Yealink phones work perfectly on our previous PBX, yet when we move them to Vital, auto provisioning through YMCS, they register no problem, but their registration changes between green and red (unreachable) and so their phones do not ring.
When we swap out the TP Link for something else, in two cases a Netcomm and one case a Mikrotik, the phones remain green. No issues at all.
This cannot be a coincidence; there must be something with TP Link. There are no firewall settings, all is default, SIP ALG is disabled, still the issue continues.
Does anyone have any experience with this?