how can I stop "cast to nearby device" pop up?

I might be watching Netflix or well anything and randomly this pop up asking me to cast to nearby device comes up. and asks me to insert a pin it renders my phone useless till it decides to stop doing it. help please! how can I stop this I have an HTC 10

from Android Forums at AndroidCentral.com - Ask a Question //forums.androidcentral.com/showthread.php?t=772802&goto=newpost
via IFTTT