Calls drop at random intervals with "400 Bad Request"

[Stijn_DC]

Hi all,

I'm having a weird issue with a client that seems to started happening overnight.

• 3CX Version, Pro annual 16.0.8.9
• Server OS, Windows 10
• Is the 3CX Server Hosted and where? not hosted, installed locally
• IP Phone Make/Model/Firmware Yealink or 3CX Softphone
• Provisioning Method: Local
• Trunk Provider or Gateway Make/Model: Telenet using a IAD
• Has the Firewall Checker passed: YES
• Are custom Phone Templates being used: NO

Client is complaining that certain calls will just drop out at certain intervals. This seems to have started at random and we cannot seem to pinpoint this issue.
when tracing the issue we can see that the Providers IAD sends a BYE request to the 3CX server and closes the connection.

On checking the traces we see the following reason for the BYE:




These drops are at random intervals and at random times of day on random numbers, so we cannot exactly pinpoint the issue.

because the IAD is connected directly to the 3CX server with a new or at least recent Cat5E cable we've also ran some stability tests and found no real issues between the devices.

Anyone have any idea what could be causing these Bad Requests?

thanks in advance!

 

[VasilisV_3CX]

Hi @Stijn_DC,

Have you spoken with Telenet with regards to why you're receiving the bad requests? It may shed some light on why this is happening and isolate the problem more accurately.

 

[Stijn_DC]

They just answered me the following:
Both calls were stopped by Customer side with SIP Bye request with
Reason: SIP ;cause=400 ;text="400 Bad Request"

This is client side error they need to look at their side to understand why their PBX stopped the call with this error.

Which to be honest feels like a "Go F' yourself"

 

[VasilisV_3CX]

Hi @Stijn_DC,

I think that if that's the case, it's best to run a Wireshark capture to see exactly who sends the BYE. Once open you should be able to ascertain this, if it's 3CX sending the BYE let me know, however if it's Telenet you can revert to them with the capture to get a less obvious answer.

For more on Wireshark and Capturing: https://www.3cx.com/docs/capture-network-traffic/
Our Academy Guide on Troubleshooting: https://www.3cx.com/3cxacademy/videos/advanced/basic-troubleshooting/

 

[Stijn_DC]

I will send you a screenshot with some personal client information with the results of the trace.
In short:
The IAD of Telenet is sending the Bad Request. But according tot Telenet its doing that as a response to a request 3CX sent to the IAD

 

[VasilisV_3CX]

@Stijn_DC, I've sent you a PM you regarding this.

 

[Jan Luijten]

@Stijn_DC,

Have u come up with any solution? We are currently experiencing the same issues.
Same 3CX Version, also with Telenet IAD (SIP Over Coax). Any suggestions would be much appreciated.

Kind regards,
Jan

 

[Stijn_DC]

Hello Jan,

I Was just about to update this case when I got home, but saw the notification

After running many, many, many tests with the Voice team over at Telenet I finally got through to them yesterday. and got the following response: "We changed some settings on our end, please check with the customer".

So far we've not had any calls being dropped.

the easiest way to check this, is to have multiple calls running at the same time and checking if only one of them drops with the bad request header.

 

[VasilisV_3CX]

Glad to hear that you managed to get this resolved @Stijn_DC. If you require any further assistance, feel free to open a new thread.

 

[Stijn_DC]

At this moment I would call it "pending Closed".
But if I have any other non related issues, I will be making a new thread.

Thanks for the assistance!

 

[VasilisV_3CX]

No problem, I'll leave this open and if you have any issues along the way feel free to update me.