There are a few reasons why you might see this problem.
Check that you are streaming to the correct address from your encoder.
Check that there are no spaces in the RTMP url and incorrect symbols, characters, or spaces in the stream name. Check especially at the end where you might not see that there is an extra space from copy and paste.
Please be sure to wait a minimum of 45 seconds before verifying the stream through the player. It takes this approximately this long for the video to propagate through the network and appear in the player. This delay in time is only at the very start of your stream.
Try streaming to the backup url. If you’ve tried these steps and are still experiencing difficulty, please contact the Stream Monkey support team for additional assistance.