I have GXP 2160 phones and several other GXP models and I have the BLF key programed and it lights up when it’s suppose to, and when I press it (if it’s green) it will place a call to the extension, but if I press the BLF Key for extension 100 and I am on a different extension the phone will not pick up the line. This feature words in Freepbx, but not here.
I am using GDMS.Cloud to configure the phones, and I have tried enabling and disabling “BLF Call pickup”, and “Force Call pickup” with no luck.
When I sent it to Grandstream they asked for a Packet capture for further troubleshooting.
For Fanvil and Yealink devices, I always set the Direct Call Pickup Code in my templates, by default its *07 in Vital (it can be custom set if you need something else). I will assume there is a similar value in for Grandstream which you just need to setup as well.