Phone connectivity issue on New Year

On Jan 1st around midnight UTC, I got a call that 2 out of 3 phones were “no longer working”. I hopped online and saw that the phones weren’t connected and out of panic, restarted the server with no luck.
We agreed to continue later. The phones (Sangoma S406) are in a remote location from the server and were configured to use the VPN feature a while back to overcome NAT issues. I got remote access to the site and looked at the phones and they had somehow switched to the none NAT configuration and were not registering. I could not figure out what was going on, so I deleted the EPM profiles and rebuilt them. The phones started registering, but were not using the VPN feature at all.

I updated the server, the modules, rebuilt the EPM profiles, but to no avail. I decided to delete the EPM profile again, delete the extensions, delete the profiles under user management and applied config.

Once that was done, I disabled the VPN server and turned it back on. Rebuilt the profiles, which in turn created the users under user management and configured the phone mapping. I then went in and edited the EPM profiles and put in the VPN profile for each phone and hit save.

Auto provisioning after factory reset was not working using Zero Touch. I verified and replaced the settings, with no luck. So I manually setup the provisioning on the phones. Saved and Hit the “Auto Provision” button. Phones restarted and started picking up the VPN config and registering. It took around 2 minutes for the phones to pick up everything and be fully functional again.

This isn’t a “issue” anymore, but I did want to bring it up incase anyone has similar issues when monday comes around. Looking at logs, I couldn’t tell if something happened (I may be looking in the wrong place) but something happened after midnight and going into the new year. I’m not sure if it’s a bug or some other reason to cause this.

Oh…before I forget:
FreePBX 15.0.17.64
Asterisk 16.20.0
Sangoma Phones S406 running version the following:
BOOT–3.0.4.33(2018-07-26 09:58:00)
IMG–3.0.4.88(2021-11-05 17:11:00)
ROM–3.0.4.88(2021-11-05 17:11:00)
DSP–9.0.3RB(Patch 1.0.16)