Oddly, "ca-test" Stopped Working For Me

I was a bit worried because for some reason I could not see google ads on my blog, but saw them no problem on other ones. I wondered if perhaps my domain was banned. However, luckily not… I finally realised it was because the "ca-test" publisher ID was not working (my ads were set to switch to this in when I’m browsing my blog).

I wonder if it’s a temporary glitch or has Google Adsense disabled the use of this?