Hi,
Could you please share the button configured for this ephone.
Are you able to use speed-dial 11 12 13?
Note::
After the speed dial is created the phone will assign the speed dial to a phone button(This is important, as there may not be an available line button). The speed dial will be assigned to the first available button, but not before any other buttons.
A speed dial can never be before a button that has another configuration