Call forwarding to Mobile when called from internal extension to extension shows a wrong CallerID

[voice11]

When extension 100 calls extension 105 and the call gets forwarded to mobile shows a wrong caller ID on the mobile. 105 has "internal calls forward to mobile" enabled.
This weird behaviour happens only in this particular situation.

No matter whichever other you call, the system will always show the right (intended) caller ID which is our main number. This correct number XXX-XXX-XXXX has been setup in multiple places. Such as Extension > General > Outbound caller ID. It's also set up at SIP Trunks > Trunk > Caller ID > Default outbound caller ID. So the system works perfectly as it's intended.
Every outbound call will show the main number (as intended). Or if a particular extension has an extension-specific ID then it will show that particular number when calling out.

External users, too work just as expected. External user call extension 105 > gets forwarded to mobile. On mobile, it will show the caller ID of the external caller. So, everything looks great!

The issue is only when an extension calls another internal extension and the call gets to Mobile it shows this weird number which is not any part of the 3CX.


I have to mention that the wrong caller ID is not particularly wrong. It's the number the SIP provider assigned to us when setting up our account. It's not our own DID and it has no role in the PBX. It's a ghost number which took me some time to figure out where it came from.
You never see this number anywhere other than in this particular situation. I have seen everywhere in 3CX, but it's nowhere to be found.

 

[voice11]

Does anyone know anything about this odd behaviour?

 

[SweetAction]

I'm going to guess it's something to do with how call forwarding to mobile is using outbound rules when it's an internal call. It's likely not hitting a rule with a CID on it or maybe with an invalid CID which causes your carrier to use it's default number.

Honestly you need to do a capture and see the flow and rules applied and also speak to your provider to find out what they are seeing.

The easiest way to solve this might just be to have your provider change the "default" on their side to the desired CID.

 

[voice11]

Thank you for the reply, Andrew. But no, it did not work, unfortunately.
And yes, I use "Unsupported" generic trunks. Been using it for years and works flawlessly. This particular issue never occurred before but I believe it must be there before as well, it just went unnoticed all these years.

Just to confirm, I went to Sip Trunks > Trunk > OutBound Parameters (then I made these changes above), right?

Thank you in advance.

 

[Vali_3CX]

@voice11
What brand is the mobile phone? Android, iOS?

 

[voice11]

Hi Vali, It's iOS in my case. But the call comes gets forwarded to the Mobile network. So it's the cellular network and happens in any OS regardless.

 

[Vali_3CX]

I might be wrong, but I was thinking it could be possible that the issue is not in the PBX configuration, but just a simple iOS/CallKit matching the incoming GSM caller number with an existing device contact - if you check the device Phone Recents for that call and tap the Info button to open the details, does it show Create contact or Edit?

 

[voice11]

Yes, it does show create contact. It's a ghost number for us. It took me some time to understand why I was seeing that number. It's an alien number to us. So yes, it's not one of my contacts.