- Plesk Onyx for Linux
- Unable to issue or renew a Let's Encrypt SSL certificate for webmail.example.com at Plesk > example.com > Let's encrypt > selecting the Secure webmail on this domain checkbox. The following warning is shown
PLESK_WARN: Invalid response from https://acme-v02.api.letsencrypt.org/acme/authz/mrkuES5ApWYKJEBElh47Ynxp03JmsjoKyADWUO0jbqA.
Detail: Invalid response from https://webmail.example.com/.well-known/acme-challenge/CYt1tP_7l1JsJVWy9iRBN7bCl8PyJyx8lVlSQis9F6c [203.0.113.2]: "<html>\r\n<head><title>404 Not Found</title></head>\r\n<body bgcolor="white">\r\n<center><h1>404 Not Found</h1></center>\r\n<hr><center>"
- Repeating the above steps issues or renews the SSL certificate successfully.
Let's Encrypt extension bug EXTLETSENC-694 which will be fixed on future product updates.
As a workaround, perform the process twice to successfully issue or renew the SSL certificate for the webmail:
- Log into Plesk;
- Go to Domains > example.com > Let's Encrypt
- Select the Secure webmail on this domain checkbox and click on Renew or OK.