How to renew ubuntu ssl certificates?

Question

ubuntu

A month ago I installed ssl on my server, I don’t remember what instructions, but after 30 days the certificates expired, I try to install according to other instructions, but still, when I enter the site, it says that there is a threat, the certificate is stitched ...
Tell me how to clear the former certificates and install new ones, preferably self-updating...

Answer 1

certbot