Connecting and disconnecting

[AC Question]

I just installed a miracast dongle last week. But except for a preview using the All Cast app, nothing else works. I cannot directly mirror my phone output to the tv using the Miracast app. I have a full HD 40" Samsung tv. When I connect thru the Miracast app, the tv goes blank for a second and then comes back to the connect screen. But when I tried mirroring using a Lumia phone, it worked perfectly. Can someone please help with this problem. Many thanks.