Website hosted on Plesk server is not accessible via HTTPS: This site can’t be reached

Symptoms

• A website hosted on a Plesk server is not accessible via HTTPS:

  Server not found

  ---

  Could not locate remote server

  ---

  This page can’t be displayed

  ---

  This site can’t be reached

• Web Server's Default Page may be shown instead of the site's content.

• The Let's Encrypt certificate can not be issued for the domain in Domains > example.com > SSL/TLS Certificates with the following error:

  Could not issue an SSL/TLS certificate for example.com Details Could not issue a Let's Encrypt SSL/TLS certificate for example.com Details No domains have passed validation

• The website works properly over HTTP or redirects to HTTPS:

  # curl -I http://example.com/ -v
  * About to connect() to www.example.com port 80 (0)
  * Trying 203.0.113.2... connected
  .........
  < Location: https://example.com/
  Location: https://example.com/

  .

Cause

SSL/TLS support option is disabled for the domain but a redirection to HTTPS might have been enabled in the website configuration/code.

Resolution

1. Log in to Plesk.

2. Go to Domains > example.com > Hosting Settings and enable the option SSL/TLS support: