codeprisma

No, the site is not using CloudFlare but your answer was helpful.
I deactivated the plugin ‘Ultimate Addons for Elementor’ and then delete it permanently.
After deletion, the iThemes Security Plugin is now working properly!

Thank you so much for your time! It was very helpful!

Following Plugins were activated when I was installing the iThemes Security plugin and it was working:
Bluehost
Elementor
Elementor Pro
Hide Page And Post Title
iThemes Security
WPForms Lite

Yesterday, I installed all of the following plugins and when I wanted to go to iThemes Security setting I couldn’t be able to go to the page; they were showing that The link you followed has expired.
I deactivated all of the following plugins but still, iThemes Security is not working.

Jetpack by WordPress.com
MonsterInsights Pro
WPForms
Ultimate Addons for Elementor
Yoast SEO Premium

I also changed the browser, clear the catche of the browser but it’s not working!