How do I fix this?
When you click o the “Open in a new browser window” button on the top right, do you still see the same error?
Yes, it does show the same error, ‘404 Page not found.’
I’ve had that happen occasionally, especially with the first output the prototyper creates. Have you tried describing what you’re seeing to the prototyper chat? If you don’t want to dig into the code, I’ve had pretty good luck with telling it where I see the 404 and asking it to fix the issue.