HP MFP 277 DW Fax Sending To Wrong Number

[575DESIGNS]

Just started working for a client who has an HP Color Laserjet Pro MFP277DW All-in-one machine.  It recently (no upates or changes that I am aware of) started having a serious fax issue.  The number you enter on the touch screen is not the number the fax machine dials.  It pulls the same unknown number adds the number you entered to the end of it and sends it out.  The result is you do not know who got the fax but the confirmation shows sent with status OK to the number you entered.  I have tried clearing fax jobs, the on-board address book is empty, and rebooting has no effect.  I have checked for updates (none) and I have sent a blank page to a known number, but it dialed this random number and confirmed delivery yet the known number never rang.  

Confused as to what could have caused this or how to fix it?  Fax was working at some point (we think) a while ago.   They don't send many faxes out.

Any thoughts?

[575DESIGNS · Accepted solution]

After posting this I checked one other thing and discovered the problem.  Somehow (or someone) had apparently entered that number as the dial outside line extension.  Not sure how that happens since they would have to run the entire fax setup tool I would think to do so and who would be needing the office fax to send to this number.  But removed the dial outside line extension and fixed the fax issue.