Few phones un-register and re-register over and over

[Jimstigator]

Good morning,

Two of approximately 80 phones are un-registering, then re-registering after a minute or two. It's happening randomly, up to 20 times any given day. What can cause this? I have done the basics, like check connections, etc. Its two phones on different switches, and none of the other phones on either of those switches do it.

The phones are Yealink VP530s if that matters.

Any thoughts?

Thanks!
Jim

 

[Jimstigator]

I was told to go into some custom parameters in the 3CX system and increase the "EXPIRATIONGRACEPERIOD" by a minute or two. This a decent solution?

 

[AndreasP_3CX]

Hi jimstigator,

This looks like an issue on the phone side firewall (NAT) - it looks like this NAT is stacking which is causing your issues.

Best Regards