We have VOIP service with Port5060, through Airband FTTP, an openWRT router, a Cisco SPA122 ATA and Panasonic DECT base and phones.
Sometimes (say 1 in 5-10 calls) when the phone rings it correctly displays the callerID, we pick it up and there is nobody there. Hanging up and trying to ring back, there is no dial tone. Talking to the caller, the remote end just keeps ringing. I think we get a dial tone back when they give up ringing.
Port5060 are blaming Airband's CGNAT and say that there is no workaround.
I will raise a ticket with Airband, but I hold out zero hope of them actually doing anything.
Are there any workarounds or are we stuck with a copper line for eve? (Well until they disappear.
Thanks for any suggestions.