I use VoIP for my home office and utilise a Grandstream GXP-1610 for this and 2talk provide the services. I recently added another identical Grandstream device in my network for use in the kitchen. Everything went well at first, but now one of the phone always loses registration with the SIP server. This never occurred when I only had one.

If I restart my entire network and both phones, they'll come back online, but only for a short while.

They have unique phone numbers for each, but sometimes when a call is dialled to the kitchen phone, the office one will ring. There's no forwarding or hunt group rules set up.

I currently use Google Wifi to run my entire network. I have VLAN tagging disabled and the main Wifi base connected directly to the ONT. An unmanaged network switch then shares that connection with the ethernet jacks around the home.

Are the two phones fighting for dominance and the connection to 2talk? Way out of my depth here and any guidance would be appreciated.