S9+ Dex

I had used to use dex wirelessly wth my samsung tv tu8500 and it just work superb
Today i press dex on my s9+ and no devices appears to use dex on
I had remove and add the tv and nothing happend
Then i had factory reset my tv still the same problem
Smart view works fine
But dex isnt
Any solutions ?

Clear data of all dex related apps