Can't forward calls to an external number

Hi Everyone,

Sorry if this question has been asked before; however, before, our phone would forward our IT group calls to my cell phone. Then about maybe 2 weeks ago, it stopped.

So I checked our Twilio logs and it showed an error that my cell number wasn’t verified, so I verified it.

No changes were made to our PBX that I am aware of. Maybe 2 years ago, all I did was go to my extension number via the web GUI and added my number as an external number to forward to.

Upon researching this issue more, I have seen some posts about adding an inbound rule or outbound rule.

Our outbound rules have 4 that have the patterns

Inbound has
Default mode

In the system events, I see the following error.
SIP Outgoing call through trunk failure.

 Content: SIP outgoing call through trunk failure. Provider name: TwilioUS2, From user: +1(our office number), To user: +1(My cell number). SIP response code: 400 Interworking, unspecified. 

This error looks like an outgoing error, so I’m sure sure if it’s related to my call forwarding issue.

Any assistance is greatly appreciated.

Thank you very much,

Which is your cell number in relation to this call. The number I’d expect them to require to be verified is the caller number, not the called number.

Sorry for the bad explanation. The caller number, my cell, is the number our office is supposed to forward calls to. Looking at the error, I am guessing that when I use another phone to call our office, our PBX is then trying to forward to my cell phone and it looks like maybe since we don’t have an outbound rule for forwarding, our PBX doesn’t know what to do?

I tried to add an outbound rule and don’t know the command code needed to tell our PBX to forward the incoming calls to my cell.

Any help is greatly appreciated.