Have you tried it with the default extensions in the system to test such a theory?
One of the things about a system THIS complex is using the existing configuration before making changes to it, then when you DO make changes be sure they worked (completely). If it turns out that cc105 works but 1005 does not ... either switch back or find the "Other" differences (or perhaps change to cc1005 LOL).
Please remember that there IS a difference in "105" and "cc105" (both are used, but each in its appropriate location, for the single phone). Agents on a standard system dial "105" (not cc105, since there is no cc on the phone's keyboard) to dial an extension. yet there is a cc in front of it when creating the SIP context.
Be watching your sip-vicidial.conf and your extensions-vicidial.conf and your asterisk output to find your issue.