PJSIP channel required error?


Our 6510 has been having an issue lately where every 2-3 days we have to reboot the PBX because calls basically get…stuck when dialing in. Our current inbound route has all calls going to an IVR which then sends them to their respective destinations. After a few days, some of these calls get stuck. They will show as active calls from anywhere from 10-15 mins in the IVR without the call being hung up. Trying to hang up the calls from the PBX webgui does not work, they just stay and no incoming or outbound calls work. We have to reboot the PBX for it to work. Today, I pulled the syslog and the only anomalies I found was that there was a fax machine that kept dialing our fax over and over (probably every 10 seconds with no answer reported) and during this time, our PBX was not receiving or making calls. After rebooting, the fax dialed us and this time, it went through and all calls afterward worked. In the syslog, I found a TON of these errors:

May 24 12:47:46 UCM6510 user.err asterisk: [20190524 12:47:46.736] ERROR[31435] res_pjsip_header_funcs.c:490: This function requires a PJSIP channel.

There are tons of these probably every second or so. My research has shown that people claim these are benign and will not affect anything but I just want to make sure because I want to find out what is causing out phones to keep going down. We have a PRI circuit going to our 6510.