911 Carrera S CD player

I have rented a 911 Carrera S.  While it does not have the 4 disc CD 
magazine option, it does have a single CD in dash Boze sound system.

I cannot get the CD player to work for the life of me.  The owner's manual

is not in the car, so I was hoping one of you could help me.  I have
pushed 
the "cd" button and tried inserting the CD and - nothing - the CD won't go

in.

Is there a trick?

Thanks