1st. Check the autoprobe.log to ensure that there are no errors, since an error will cause only some instrumentation to be loaded.
2nd. Make sure there is activity on your application.
3rd. As Lynn identified, there are common Frontends that we watch for out of the box. If your application uses something more abnormal to start transactions we may not be recognizing it, or may not be identifying it as a Frontend.
You can also upload the autoprobe log to autoprobe.net to see if there are extensions to monitor your application's Frontends.