StreamYard to ManyCam via rtmp?

Is it possible to use rtmp to broadcast from StreamYard into ManyCam on the same computer? I have tried setting up the a rtmp server in ManyCam (I can see the message "Start streaming to rtmp://0.0.0.0:1935:testtesttest on the ManyCam screen) but I get this error from StreamYard even when trying all three rtmp options in ManyCam (any interface, Realtek family control and software loopback) all three had this error message from StreamYard in about 15 seconds:

We’re having trouble streaming to your destination. Is it possible your RTMP server URL or stream key are invalid? We’ll keep trying and let you know if it’s resolved. Please check the destination to ensure the stream looks okay. If this continues for awhile, try creating a new broadcast. Or just remove this destination from the broadcast then re-add it.

Is what I am trying to do possible? Thanks for your help!