Cisco phone calling wrong directory number

[CTOSHRP]

My phones are not dialing the correct number for a DN. If dialing 100, which is for say the front lobby, all the phones actually dial 400 which is the galley. 

I've tried to look at the dialed number analyser and it's showing if I dial 100, from a certain phone, it goes to 100. But that's not what is happening. Not really sure where to look next, any help? 

[Roger Kallberg]

Look in the SDL trace files to see what actually happens during call routing logic.

[Maren Mahoney]

I would also try doing a search for 100 in the Route Plan Report in CUCM to see if there is a Translation Pattern or other capture of 100 that is sending it to 400. Can I assume that there is no call forwarding set on 100?

Maren