Can’t purge page

When I go to Shift 8 CDN settings/Purge and try to purge, it says only, “Error Detected : unknown”

I also have a new entry on the Gowalle Guestbook, but it is not displaying. That’s why I wanted to purge the page.

Following is the info that that I was told to copy into my message about the configuration of the site.

Shift8 CDN Debug Info

WordPress Version: 6.6.1
Current WordPress Theme: Divi version 4.27.1
Theme Author: Elegant Themes – https://www.elegantthemes.com
Theme URI: https://www.elegantthemes.com/gallery/divi/
PHP Version: 7.4.33
Active Plugins:

• AddToAny Share Buttons?(1.8.11)
• Advanced Post Types Order?(5.3.5)
• Akismet Anti-spam: Spam Protection?(5.3.3)
• Broken Link Checker?(2.3.0)
• Classic Editor?(1.6.4)
• Coming Soon Page, Maintenance Mode, Landing Pages & WordPress Website Builder by SeedProd?(6.18.5)
• Enhanced Media Library PRO?(2.9.4)
• Featured Image from URL (FIFU)?(4.8.9)
• Google Analytics for WordPress by MonsterInsights?(9.0.0)
• Gravity Divi – Gravity Forms Styler for Divi?(2.1.0)
• Gravity Forms?(2.8.16)
• Gravity Forms Akismet Add-On?(1.0)
• Gwolle Guestbook?(4.6.2)
• Imagify?(2.2.2)
• ManageWP – Worker?(4.9.20)
• Shift8 CDN?(1.68)
• Shipper Pro?(1.2.16)
• WPMU DEV Dashboard?(4.11.26)
• WP Rocket?(3.16.4)
• Yoast SEO?(23.2)