Unable to access the Updates & Upgrades page when the server hostname is hosted on the Cloudflare side: ERR_CONNECTION_TIMED_OUT

Symptoms

• Unable to open the Plesk > Tools & Settings > Updates & Upgrades (Updates) page, with the error below:

  This site can’t be reached
  ERR_CONNECTION_TIMED_OUT

• The Updates & Upgrades (Updates) page successfully opens via https://203.0.113.2:8447 link( where 203.0.113.2 is the server IP address).
• Using the DNS Checker utility it can be found that the DNS of the server hostname is hosted on the Cloudflare side:
  

Cause

The Cloudflare does not support proxy over 8447 port.

Resolution