Server check
There are many different useful tools for checking your server and/or website for performance, technical conformance and quality. I found one today while trying to debug my certbot renewal problem:
https://check-your-website.server-daten.de/
Results on 2023-05-15 https://check-your-website.server-daten.de/?i=34a10744-f513-4509-ad27-352612ce1ead