Unknown Diagnostics Error

I’m trying to setup the Matomo WordPress plugin and can’t get past the following error.

“There are some errors in the Matomo Diagnostics System report that may prevent the plugin for working normally.”

The link in the error takes you to the Diagnostics page. If I look at Matomo’s menu in WordPress’s side menu there’s a 1 in red beside the link to the Diagnostics page. This suggests that there is an error on the Diagnostics page the same as the error message above suggests. However, when I go to the Diagnostics page there are no errors. So, how do I fix what I can’t see, get rid of the error message, and make sure the Matomo plugin is working correctly?