I changed a couple of settings on the Extensions page:
Changed Port to 5061
Changed Transport to: TLS Only
Now the phone stays registered for good, but when making a call the first call will fail, But the Second call will go through.
I got Cisco Meraki on the phone and took a couple of packet captures, Looks like the phone is resetting the connection. I don’t know why it does that. But before it does that it receives and encrypted alert from the server.
Update on Network Topology
Remote Site ( Where phone is located )
Sangoma S705 --(172.16.40.2)-----> Meraki Switch ------> Meraki MX65W ----(Public IP) ----> Fios ONT
FreePBX Server 14 --------> Meraki Switch -------> Meraki MX450 ----(1:1 Nat for FreepBX-dedicated IP) ----- Fios ONT
MX450 Handling the entire /24 subnet of the Static IP’s assigned to our organization.
PS… One more thing I noticed is when this happens and I Press the DND key the Presence wont light up red and the DND when the Reset is done. But on the Second call if I press the DND key both DND and Presence will light up Red.