What if my TV is connected via Ethernet and my Macbook on wifi?

I have an issue with the "new" airplay. In the past, it was easy: I had an icon in the upper menu, clicked on it and could select my TV for example and my phone, macbook, macbook-pro and even my Imac used the TV screen. It was perfect. But now, everything has changed and it does not work anymore. You should know that I try to use, as much as possible, the Ethernet for my fix devices s

uch as my imac and my TV. Bu even as it is the same network, my airplay does not work anymore....