This error means that an internal exception was raised in Studio's Python code. In this situation, Studio writes out a stack trace to its log file:
/edx/var/log/cms/edx.log |
You can find this stack trace by opening the log file and scrolling to the bottom.
If you ever see errors along the lines of the one below saying some table doesn't exist, it means that there are migrations that haven't been run that you need to run.
Table '<name_of_some_table>' does not exist |
The error should go away once migrations have been run.
If your issue is not listed on this page, there are many other resources that might help you: