Repeated Missed Calls & Notification Spam – 3CX System Issue

[tila]

Hi everyone,

we're experiencing a strange issue with a 3CX system (Version 20.0 Update 5 (Build 551 Release).

Problem description:
We're receiving dozens of missed call notifications for the same call attempt within seconds. In the 3CX call log, these show up as unanswered calls terminated by the destination (see screenshot #1).
On the user side, our colleagues receive a flood of email notifications from the 3CX system for each missed call (see screenshot #2).

What we’ve observed:
This does not happen consistently – it occurs sporadically.
Only one user reported this issue so far - not sure, if it is a user specific problem.

Has anyone encountered a similar issue or can point to a possible cause?

We’re currently suspecting either a misconfiguration, a client issue, or something within the 3CX call flow logic.

Thanks in advance for any insights or advice.

 

[paulodagraca]

Hello tila

Is the extention set to DND or other status with 'End Call' by any chance?

I have seem 'something' like this, where the call did not drop, but the SIP provider did setup the call many times, resulting in many 'lost calls'.
So not sure, but just asking.

 

[K_SAK]

Hi,

This call is coming directly to their extension? Ring Group? Any forwarding rules that might be looping the call around while they are in some Away state?

 

[m.w]

Hi,

we have the same Problem with Queues, there are missed calls every seconds when the person is on a teams call.
So we have tried the Teams sync and there is a bug with "the hang up after a call status presence".

I found something about the cause-code, but dont know there is a parameter in 3CX to change the PSTN?

https://itbasedtelco.wordpress.com/...n-busy-cause-missed-call-storm-notifications/

 

[richiewhite]

Is there a DID assigned to the user? I can't see whether you've filtered the log so it's hard to tell whether it's being directly routed or there's a queue etc sending it through.

3cx seeing the user terminating the call indicates that the user's device is cancelling it. Maybe a device side DND, depending on the device it's probably sending a message like a 480-Temporarily Unavailable, if it's a direct dial call then your SIP trunk provider may be seeing the response as needing a retry and sending another invite.

 

[m.w]

So, yesterday i opend a ticket on the 3CX helpdesk with no luck. 3CX says its a fault on Microsoft side.
You can stop this bug when you activate the teams<->3cx sync but there is another bug with the presence - DND oder away hang up after a call when the presence in for exmaple "busy" in teams.

After a view microsoft sides the bug is identified and there are a solution with my post but 3cx does not support "sip message manipulation".

So no chance to stop this error, my next step is to deactivate the "busy on busy" in teams.