When I add Quiz Results Slide...

Hi timucin,

I'm happy to help!

First, you'll want to confirm you're working locally when editing your file. You can try deleting the results slide and re-adding it, and if the issue persists, try importing your slides to a new project file. You'll also want to ensure the correct slides are selected in Quiz Settings, as shown below.

If you continue to see the first error message about something going wrong, I suggest trying a Storyline repair. The second screenshot you shared might have something to do with your file, specifically. If you're willing to share your file here or privately in a support case, we'd be happy to take a closer look at what's going on!