I rarely used this feature but I just tried repro'ing and I get the error message too. Might have been something that Google did on their end. They're always changing things.
Note that I'm using a Google Nexus 7 2013 Wi-Fi model running Android Marshmallow.
Other than that, don't expect updates; PS Touch was discontinued on all platforms.
Yeah I was thinking that too: google's changes. Ah well.
And yeah, what the heck Adobe? Touch was an amazing product. I'm glad I got it when I did, but wish they'd keep on with it. The other products they have for iOS I find not as useful by far.
I think I recall hearing something that have more plans for mobile that will help fill in the gaps left behind by PS Touch. What that may be is anybody's guess. There's Photoshop Mix and Fix, but those are pretty specific apps so Adobe has to find something to fill the space for us creatives.
This may be all moot, however, in the next few years; 2-in-1s and tablets that act like laptops (like Microsoft's Surface line) are using Windows 10, which means desktop Photoshop, the granddaddy of them all.