I'm dealing with an issue regarding a few Mitel 6930IL IP phones we have in our office. There's one user claiming that when someone calls their cell phone from these phones, the call never comes through. I've already checked with our network team responsible for the phone system, and they assured me everything is functioning correctly on their end, suggesting that the problem lies with the user's cell phone provider, Verizon. However, the user reached out to Verizon and they also said there are no issues. The user reports that their phone doesn't ring at all, whereas the caller using the Mitel phone hears it ring once before it abruptly stops. I'm not sure what the next steps should be to diagnose or resolve this issue.
4 Answers
You should escalate this issue to your networking team if you haven’t already. They can run packet captures to find out where exactly the call is dropping off.
Does calling from the Mitel phones to other numbers work fine? If there's another Mitel phone nearby, you might want to swap them temporarily to eliminate the possibility of a faulty port or switch. You could also try a factory reset on the 6930 to see if it resolves the issue.
There are various VoIP protocol tools that can provide call details. Your call logs should show a SIP response code, which is similar to HTTP responses. If the call is being rejected by Verizon, you might see a 400-range code like 480. It's also possible that your phone system has a poor routing to Verizon or even consider testing calls to other mobile numbers since sometimes numbers get blocked for spam reports. Also, check that the user isn't blocking unknown numbers, which is a common issue.
That's interesting! I didn't consider that the user might have call blocking enabled. Other mobile numbers seem to work fine; it just seems to be a problem with his number.
Have you personally tried testing the call to see what happens? Sometimes, experiencing the issue firsthand can give you more insight into what's going wrong here.
Yeah, I tried it out and got the same result – the call just doesn’t connect.
Okay, I will go back and bring it up with them. Thanks!