FreePBX on cloud with Remote IP Phone clients,randomly becomes UNREACHABLE

Hi I’m having an issue with my FreePBX here’s my setup.

FreePBX is setup on cloud
I connect my phones on it remotely.
My softphone can connect to it with no problem, it does not experience disconnection or any problem.
However my IP Phone (Polycom 321) will randomly becomes UNREACHABLE. this happens everytime and it will take about an hour to reconnect again or sometimes it will not connect forever you have to reboot the physical phone.

I’m using a pFsense on my network where my SIP phone (client SIP) are connected. im connecting without any VPN. please help me out here im running out of ideas. it’s been a month now. tested all i can.
what information do i need to provide please tell me.

This is often caused by having two SIP devices behind the same firewall. You’ll need to change the port that the phones listen on. The softphone will probably pick a random port well away from 5060, which is why that’s working.

Try changing the port the polycom sends SIP traffic on to something more than 10000, and also ensure that it’s forwarded correctly in your firewall. You may also need to disable SIP ALG in your firewall.