Can no longer "Mirror" or "Airplay" to my Vizio TV

This is odd ... my Vizio TV used to show up as a "Screen Mirroring" option on my iPhone as well as an "Airplay" option on my MacbookAir. Suddenly, my TV is no longer appearing as an option on either? I've gone through all the recommended steps .... rebooted my laptop, phone, TV and router; ensured everything is on the same network; have the latest OS/iOS, and nothing. However ... if I "cast" a video by selecting the little box icon with the little wifi symbol in the lower left corner, it works fine! I get an entire list of available devices in my home, I can select my Vizio TV and it works great! Any ideas why Mirroring/Airplay is not working?