When clicking Apply Config, incoming calls stop, need to restart

When the client hits Apply Config after making changes (to hours or anything in the system) they state that incoming calls stop coming in, until they reboot the system.

Here is what was sent in:
“ok today i changed some times on the phone system for opening hours and clicked apply config. calls began to not come thru so i rebooted system so its still happening. I cant make any changes without having to reboot whole system”

Any help would be appreciated.

So to be helpful there needs to be a lot more information.

Are there any errors?
What happens when you call in?
What happens when you dial out?
What do you see in the console?
Is Asterisk Running?
What happened to Jimmy Hoffa?

There needs to be some basic troubleshooting to even get a direction here. Essentially rebooting is the nuclear option so who knows what was broken or what is getting corrected in reboot

I suspect that this is related to the PJSIP transport reload being enabled. But as James mentioned, you’ll need to provide logs of failing calls, errors etc.