Hello @gewoonwatgroener
As I tried checking this on my end, it seems to be working fine!
Here is a screencast – https://share.bsf.io/X6ulxD8P
Can you confirm if there are any other plugins that might be causing this?
Here is what you can do to check:
1. Please try switching to a default theme, like Twenty Seventeen, and check whether the issue persists. If yes, then it is not the theme that is causing the error.
2. Deactivate all plugins temporarily except the “All In One Schema Rich Snippets” and see if that solves the problem. Then, activate plugins one by one to see which plugin is causing the problem.
This is a general debugging process that all WordPress support teams perform to find 90% of the problems. Here is a video that explains the process. If you’re concerned the debugging process might break your website, you can take a quick backup of your website as explained in this video.