If other phones work besides CIPC and you're on call manager 8.x, check out this bug http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCtx18810.
CIPC doesn't support secure URLs so in order to get CIPC working you would have to create a new EM phone service where you copy the non-secure service URL into the secure-URL field. For some reason CIPC looks at the secure-URL field even though it doesn't support it, so that's a workaround to get it to work.
If all phones are not working check out this bug CSCtx59395.