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SPA112 drops incoming calls upon answering them

A few weeks ago I installed a new SPA112 for use with the VoIP-service of my provider (Solcon, NL) and have not yet found a solution for this problem.

Outbound calls work fine; no drops, no connectivity issues, works just fine.

Inbound calls pose a problem: I am unable to answer calls. Incoming calls ring the phone just fine, yet upon answering (aka, taking the phone off the hook), the connection is dropped immediately at the other end (as shown on my mobile phone) and after a few seconds I also hear a disconnection tone. Caller ID is shown just fine and calling back (*69) after encountering this problem (or just missing the cal) also works (being a outbound call).

I've already enabled logging and made a few test-calls, yet the cause of the problem is still unclear to me. Attached is a (slightly censored to remove phone numbers) version of a syslog file, including boot and receiving/answering one call from my mobile phone. As can be seen, registration is good and the initial connection setup seems just fine. At line 1057, RTCP is reported to be up, which I suppose indicates a voice connection has been established. However, next thing I see is that I receive a BYE message from the server, thus causing the SPA112 to disconnect. I'm not entirely sure why this happens and my provider hasn't been very helpful so far.

The SPA112 is behind NAT; my router is configured to forward all the relevant ports. Enabling the "DMZ"-functionality (basically forwarding all unused ports) didn't change anything either, so I don't suppose that's the problem. The SPA112 is configured to use STUN and sent NAT-keep-alives (though my SIP provides doesn't seem to recognize them, causing those various SIP 404's to show in the logs, that shouldn't cause any problems as far as I understood the specification, right?).

Also, I'm not sure whether this is related or not (it might be given the problem description, but the log files seem to point in another direction?), I'm also not able to hangup/reject incoming calls during ring. My phone is a fairly standard, cheap, DECT phone. Not sure what brand it is (I'm not at home while writing this), I'd guess Siemens.

That's all the information I could think of for the moment. I hope someone here has any idea as how to solve this issue, and if you require any more information, just ask and I'll see what I can dig up. Thanks!

VIP Blue

SPA112 drops incoming calls upon answering them

Well, according SIP messages flow, the call has been BYEd from calling switch side. So - ask your VoIP operator why it's switch is aborting your calls prematurely.

Of course, you can assume it's problem with something on your side and you can play with settings. It will take take time, you hit the reason or you may loose. It is just lottery. If configuration on your side is not compatible with something on providers side, then provider should tell you where's the problem.

I have the only idea - your NAT/firewall is misconfigured, audio packets sent from provider's side are rejected by a ICMP and it trigger call release. But it's just idea.

Community Member

SPA112 drops incoming calls upon answering them

Thanks for your reply! I'll take a look at that, and try again if support can provide me with any more details. I'll check back if I happen to fix it.

Community Member

Two years later I report back

Two years later I report back since someone just voted they experience the same problem. How I solved it? Well, I kind of didn't. In the end, I decided to just no longer use the VoIP-service of my provider (Solcon), since they were not helpful at all in resolving the problem.

I switched to a specialized VoIP provider (CheapConnect in my case), and after just filling in the basic account settings in the SPA112 everything worked like a charm! So, whatever the problem was, it was at my old providers' end, and my new provider has worked flawlessly so far with the SPA112.

VIP Blue

Some cheap services are so

Some cheap services are so expensive to be used ...

Switching service provider may be best solution of some issues. That is it.

Thank you for the feedback.

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