1:when I execute the commd “sudo certbot --nginx” ,the error “Failed authorization procedure. irisnet.org (tls-sni-01): urn:acme:error:unknownHost :: The server could not resolve a domain name :: No valid IP addresses found for irisnet.org” appears .the “irisnet.org” server start at localhost,i use the nginx “proxy_pass” and modify the file “/etc/hosts”.why?
2: because it appears error ,I execute “sudo certbot --nginx” many times ,final,other erros appears “There were too many requests of a given type :: Error creating new authz :: Too many failed authorizations recently”,why?
If you want a certificate for a private network or localhost service, you can use a self-signed certificate—you can make one with openssl or for example the generator at
Then you can add it in your own browser and the browser will accept it from then on.
A certificate authority like Let’s Encrypt is trusted by browsers and so the certificates that we issue have to be given only to the people who operate particular public sites—because if we give you a certificate for irisnet.org, we’re confirming to all Internet users that you are the operator of irisnet.org, which is not correct from the other Internet users’ own point of view.