I was wrapping up lab2 and had ~20 minutes left on the 2 hour clock. The Jupyter notebook in Sagemaker studio was working fine and had not timed out. When I hit submit on the Vacareum age, it said I was signed out and asked me to sign in. I didn’t have credentials, of course.
I had to start another lab session, copy the notebook etc and then submit to get credit. Hope this can be fixed in future.