"Finding Control Channel" means the scanner has locked on a Talkgroup ID, but cannot find the control channel or frequency associated with that TGID.
There are numerous reasons why this would happen. Some of which are, the correct site isn't programmed correctly, is locked out and, as noted above, is too far from the scanner.
A little more information on where you are, which system you are attempting to monitor and if possible, posting your program file might help us to get you on the right track.