Outbound calls dropping almost immediately

[tdxvoice]

Around 3/20 I began experiencing outbound calls via voip.ms from my 3CX PBX dropping. The symptoms are typically that the call setup completes and appears to connect, but almost immediately the call does one of the following:

1. ends up at a generic voicemail greeting where it says "The number <it says nothing here> cannot take your call"
2. terminates to something like a modem carrier tone
3. terminates to dead air
4. simply drops

If you know 3CX, you know that you hear ringback from 3CX until the call is handed off. In these cases, the 3CX ringback goes on for a while, and the drop happens right after the ring tone changes, letting me know it finally connected.

I have traced one call (dead air) where I see the RTP stream from my end out looking normal (1700 packets), but the inbound stream cuts off at 1.5 seconds with only 77 packets.

I assume this is due to FCC STIR/SHAKEN regulations or something? It seems to happen mostly with calls that terminate to mobile carriers, but I haven't had a chance to completely chase that down. Is anyone else seeing this and have you found anything to do about it?

Oh, and yes, I have opened a ticket....5 days ago, with 2 subsequent chats and promises of we'll get on it, and I haven't heard anything back from voip.ms.

 

[Charles_3CX]

If the call is passed to the trunk, the call leaves 3CX, then this will need to be checked by the VoIP provider, in this case, as mentioned by VoIP.MS.

 

[tdxvoice]

Thanks for the reply. I certainly understand that. I'm looking for any other industry experience with what may be happening here as my searches seem to be pointing to more than just voip.ms. So I'm looking for thoughts on what might mitigate this. freecallregistry.com? robocall mitigation database? Etc.

 

[Alphabetic]

I'd expect you to experience a consistent issue if this was 3CX.

Push voip.ms - though, if their support isnt up to scratch i'd look at an alternate provider.

you should set up a test SIP on someone else to see if the problem follows.

 

[JeffinAR]

Same issue. Outbound call rings once, then silence. The receiving phone continues to ring, but when you answer it there is nobody there.

Started about 3 weeks ago.

 

[Alphabetic]

When did you last perform a) restart b) firewall test?

 

[tdxvoice]

This thread really hits the issue: https://www.3cx.com/community/threads/cell-phone-carrier-false-spam-filtering.136794

Ultimately moving to a new SIP provider has been the most reliable so far. I knew this was never a 3CX problem, but getting the carrier to take any responsibility has been a nightmare, even after providing packet dumps and everything else! In the process of moving all my lines away from voip.ms now.