cert

Hi, i want to mirror two spins of LMDE and Ubuntu on my vs2-free but for this i need a letsencrypt cert and for this i need a full editable subdomain. Did anybody knows a free provider for free subdomains ?

I have set up and am running 4 different servers for clients and myself, three Debian 11 and one Ubuntu 20.04. I thought I set them all the same, but one of the Debian servers shows not secure when going to example.com/phpmyadmin. All my other sites are secure; I have a wildcard cert installed...