Sitejet Builder can not be opened for a Plesk domain: Error: Could not connect to Website Builder API

Symptoms

• Sitejet Builder cannot be opened for a domain in Plesk. The following error is displayed in the Plesk UI:

  PLESK_ERROR: Error: Could not connect to Website Builder API

• The same error is also recorded in /var/log/plesk/panel.log.

Cause

Plesk cannot reach the Sitejet API endpoints on port 443. This is required for Sitejet Builder to function. The affected hostnames are:

• api.sitehub.io
• api.sitejet.io

Resolution

1. Connect to the server via SSH.

2. Check whether outbound traffic on port 443 is being blocked:

   On servers using firewalld:

   # firewall-cmd --list-all

   On servers using iptables:

   # iptables -L OUTPUT -n -v

   Note: If the server is a VPS or dedicated server with a hosting provider, check whether outbound traffic restrictions are applied at the hypervisor or network level, as these would not be visible in the server's own firewall rules.

3. Allow outbound HTTPS traffic to the Sitejet endpoints if it is being blocked. The firewall rules can be managed with the Plesk Firewall extension.