We have about 20+ GXW4248 ATA's and a couple of GXW4224 deployed at various location for the same customer. I have had constant issues with random loss of registration.. All the IP phones are working great. When logging into the Grandtream GUI it still shows the ports registered. A PCAP from the gateway shows no SIP activity until a reboot

Tech support gave me a new Firmware to try, 1.25.2, which isn't generally available yet.

I think the issue is with LLDP. The IT uses LLDP to assign all VoIP devices to a voice VLAN. I disabled LLDP in the Grandstream and set the set the VLAN ID to the voice VLAN. So far the ones I set this way are not loosing registration, even when they have firmware 1.21. The ones with LLDP enabled at the same locations are still losing registration. Eventually I will disabled LLDP on all gateways.

They had been working better on the Meraki switches because those switches did not use LLDP, and the Grandstreams stayed on the data VLAN

I know that the Web GUI locking up and loosing registration are not exactly the same thing, but I thought I would just mention what I have found. Maybe it will help someone having similar issues

David
Tele Express Business Systems