Losing 70% of inbound calls

I’ve tried, but got nowhere to try to diagnose why I lose so many incoming calls. Symptom is that a customer calls my shop #, and it never rings. Just terminates the call. Occasionally the call will go through and ring at the shop, and the call can be answered normally. Often it seems sending and outbound call will allow an inbound call to come through. Haven’t found a consistent pattern though.

I’ve searched a lot seeking answers before posting here, as I feel terribly ‘unworthy’ of asking for help. My setup will explain why I feel unworthy.

I use Telnyx as my SIP provider.
I host FreePBX on a Proxmox VM. I’ve used FreePBXv14 for years, about 6 years. It seems recently the inbound calls failing to connect have gotten bad. I don’t remember complaints for a while, except occasionally. I tried a new install on FreePBXv17, but the issues are identical.
I run the PBX behind a consumer grade TP-Link Archer A9. I’ve found no ability to check firewall logs on the router to see if it could be the issue.

Telnyx will show a SIP Call Log like:

192.76.120.10 73.12.1.41
5060

INVITE

INVITE sip:1xxxxxxxxxx(my shop #)@xx.xxx.xxx.xxx(my shop ip):5060;line=zp

[1][udp] 2024-09-28 14:23:14.203 -04:00

  • 0.000 s|

It attempts the 100 INVITE 3 times then that’s the end of the log.

Again, sometimes the call goes through fine, more often it does not.

Outbound calls work 95% of the time. Sometimes it seems like dialing certain numbers will always yield a busy signal, or a call that won’t complete. But the bulk of my woes are incoming calls. Cannot figure out what is going on.

Thanks in advance for your advice.
Phillip

Confirm that Proxmox is using bridged networking, i.e. that the PBX local IP address is in the same subnet as other hosts connected to the TP-Link.

Confirm that the Comcast modem is in bridged mode, i.e. the TP-Link WAN interface has your public IP address.

Unless already short, set Expiration for the trunk to 120.

If Qualify Frequency is long, set it back to 60 (the default).

If you still have trouble, report whether the Asterisk log shows the trunk going unreachable then reachable again. If not, run sngrep and report what, if anything, is shown for failing incoming calls.

The fix may have been stupid and simple. If this cured it, thanks so much Stewart1! I was verifying everything you mentioned, and the public IP that my router has is not the same as the Asterisk SIP Settings external address. I wonder if my modem grabbed a new IP address at some point. The Telnyx call log showed both the public IP address and the IP address listed in Asterisk SIP Settings which was close, but didn’t match the router public IP. I’ve matched the Asterisk SIP Settings IP address (which it grabbed itself when I clicked the Detect Network Settings button), and tried some more calls. The IP addresses all match now.

I’ll report back if my connection rate %s increase.

Hopefully it was that simple! Thanks again!

(I also did set Expiration to 120, it was 3600), everything else checked as you mentioned.

A conclusion to this thread. Stewart’s advise of checking the basics was what I needed to hear. It felt too simple, but I asked for advice, and was given some. So I was going to follow it, and found that my public IP wasn’t setup properly.

I assume that my internet modem at the shop grabbed a new IP somehow sometime. Since I made that single adjustment, my incoming phone connection rate is averaging 99% over several days. I’m extremely thankful for the help.