MacBook Air stopped recognizing Vizio TV via HDMI

Hello,

I've been connecting my 13" Mid 2011 MacBook Air to my Vizio smart TV with a Thunderbolt to HDMI cable for a while now to stream online television. It was very straightforward. (Forgive me if these descriptions are slightly off, it's to the best of my recollection). With power adapter connected to the laptop, once the cable was plugged in, the TV/HDMI as well as the choice for the Built In display choice both showed up in the Preferences Display panel. I'd select the HDMI connection, go to the "input" panel on the TV, select the appropriate HDMI input, and that was it. Connected. Lately I'd been having trouble with some buffering, and one suggestion was to connect the TV as another option in that Preferences panel on the Air. I unfortunately don't recall what that connection/option was called. But I did it, there were options for resolution offered, which I lowered from 1080 to 720 (another buffering solution I'd come across). Everything connected fine, and the whole setup streamed my program with no buffering whatsoever. I felt like I'd addressed my buffering issue. Until...

The next time I went to connect the TV, it didn't appear in the Preferences Display panel. In fact, the panel itself looked different, simplified. I've tried the "Hold Option Detect Displays", reset SMC, zapped PRAM, and nothing.

For the record, the Macbook Air still connects to my desktop ViewSonic monitor via a Thunderbolt to HDMI adapter connected to an HDMI cable. In fact, I thought doing that might reset whatever was causing the issue, but it didn't.

I'm trying to determine if changing the connection type messed things up. That's the only explanation I can come up with. Any feedback is welcome.

Patrick