When launching a connection via the Web interface, you see the error "No Computer available"
Most of the time, this is a genuine message and you need to provision more machines or make sure they are in a ready state. However, if you find you can connect to the same app via AppPortal and PNTSC then it could be the problem outlined below.
We have seen instances where this is caused by corruption in the Website Farm Config file.
Create a new farm in the Admin Website and connect to this instead. If this works, delete the old farm so the Users automatically use the new farm.