Yealink SIP T-21P constantly re-registering

FreePBX 15.0.17.24 / Current Asterisk Version: 16.15.1 / all modules up to date

/var/log/asterisk/full shows a Yealink SIP T-21P remote phone constantly re-registering: https://pastebin.com/wQ0ck2XQ

Here is the output from PJSIP SHOW ENDPOINT https://pastebin.com/C1qNugRu

Any help to determine why this is occurring would be appreciated.

Reachable/unreachable is not a registration issue. The PBX is not receiving 200OK packets back from the device after sending an OPTIONS packet. Usually this a misconfigured router/firewall in between.

SonicWALL calls it “Consistent NAT” under the VoIP section - don’t know what kind of router the PBX is behind, but something like this is what is causing the problem.

@lgaetz Thanks for your reply. FreePBX is behind a pfSense firewall, and I believe the remote phone is behind a pfSense firewall also. There are a number of remote phones connected to FreePBX and they aren’t showing this issue, so I’m going to assume that the issue is with configuration on the remote pfSense firewall, and I will work with a colleague to resolve the issue.

@GSnover Thanks.

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