Hi @jaqo,
Glad to hear that you are unstuck!
If you are experiencing issues with the Knit button on RStudio Cloud specifically (especially if they don't reproduce elsewhere), would you please make a new topic with the errors you're seeing and any steps to reproduce them?
If you are experiencing issues with the Knit button on your desktop, you could start a new topic in the R Markdown category -- but you might first check to see if anyone has encountered the same error(s), in case someone has already posted a solution there.
Good luck!
Best,
Mel