I ran into issues connecting to the database after trying to get back in to a tutorial after a few days of a break.
The solution that worked for me was to start a new tutorial by loading the json file. You can modify the json file to start where ever you want in the tutorial. Right click the link for the tutorial to open in a new tab, copy the code to a code editor. You’ll find a “steps” array within “levels”. Delete any of the level objects (sets of curly braces {}) for the levels you’ve already completed. Save it, and then when starting the new tutorial, select the file option, and load the file you just modified.