Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. https://crt.sh/?q=example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
Visible Content: Not Found The requested URL /.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de was not found on this server. Apache/2.4.25 (Raspbian) Server at remote.megaray.com Port 80
http + / and https + / doesn't answer, http + /.well-known/acme-challenge answers with a correct http status 404 - not found.
Just to clarify, if your are using Certify The Web you would normally run it on your actual server so that when certificates automatically renew the updated certificate is then applied. From your description it sounds like perhaps you requested the certificate on your PC then applied it to a server.
You would need to repeat this at least every 90 days to keep a certificate valid that way, if that’s how you are doing it, so setting it up on your server is preferable.