Just purchased and had installation of UX5000 system and now trying to use the CALL FORWARDING OFF-PREMISE feature which seems pretty straight forward to use... CALL1, *4, 6, #9, mycellnumber, HOLD, SPK ... but when I press the 6 key for type of device all I get is a busy signal and then nothing in the setup continues.

Anyone know what has to be done to allow to use this feature?