I have a feeling the error is correct and the userid you are getting are invalid. When you tonumbered them, they returned nil so that might mean your userId variable contains something other than a number
Even though you printed the userid and it looked fine
Type string.len(userId) and check if there are extra spaces. Idk anymore. Can you show the code you used to save their data and how you created the key? I am running out of ideas
Gtg to school now so won’t respond for awhile. Other devs could give you a hand