Have you checked your router/firewall logs and disconcertingly see connections to an unknown IP207.246.119.209:3478 from your Grandstream VOIPphones?
You're not alone and the Grandstream forums have discussed this issue.
However, even their own staff d........
In our 2024 VPS Server/Cloud Buyer's Guide, we place the location of your VPS/hosting/server as one of the priorities that is often overlooked.
2024 Update - Datacent........