Hi there, I am using my trailhead playground and do not have Permission Set Groups. Cannot create a new trailhead playground for some reason, it shows wait for Robot few minutes "Please hold while our robots build your Trailhead Playground. This may take a few minutes..."  

Then it give error:

We were unable to create a Trailhead Playground for you. Please try again.

Tried many times and fail.

Any idea or thoughts would be great . Thanks