I had a similar problem with a Samsung Home Theatre. I got it repaired (new main board) under warranty. It's worth trying a full reset, and a different cable. Luckily, I had another Anynet+ device that was still recognised, so I knew the TV was OK.
this can actually be for anyone to answer, because I certainly don't have one!
Starting tonight, when I turn on my samsung C6500 blu-ray player, my Samsung tv does not automatically switch over to the dvd player- it has automatically switched over to the blu-ray player since the first day we hooked everything up. I'll get the "source" menu to come up on the tv, and click the HDMI-CEC tab. I get a screen that says "connecting to anynet+ device", but after a few seconds, I get a screen saying that the anynet+ device is not connected. However, if I select HDMI-2 (where the blu-ray player is connected to), I can get to the blu-ray player without a problem.
To further add to the goofiness, if the blu-ray player is powered off, I can turn it on by going into the "source" menu on my samsung tv and clicking the "HDMI-CEC" tab. So I know that there's a "connection" between the blu-ray player and the tv; the tv just doesn't recognize the blu-ray player as an anynet+ device.
here's what I've tried: unplugging the blu-ray player for 30+ seconds and plugging it back in. using a different HDMI cable on the blu-ray. Doing a factory reset of the blu-ray player (which I did because the blu-ray player started acting crazy on powerup- it would read out "load", then power off, then power on again by itself, read "load", then power off, etc...). I used a different HDMI input on my tv.
All these steps still result in a blu-ray player that isn't recognized as an anynet device. Having to switch HDMI inputs isn't that big of a deal- the only reason I'm concerned is that before tonight, turning on the blu-ray player would result in the tv automatically switching to the blu-ray hdmi input. When a device drops a "feature" like that, I start wondering what else it will drop in the future!
Any help/advice from anyone would be most appreciated!