The browser is being bounced between two addresses in a loop. There are four common sources.
1. Duplicate HTTPS redirects
If you have enabled Force HTTPS Redirect in cPanel and added redirect rules to .htaccess and enabled a "force SSL" option in a plugin, they fight each other. Keep one only.
2. Cloudflare SSL set to Flexible
Flexible mode tells Cloudflare to reach your server over HTTP while serving HTTPS to visitors — and your server redirects it straight back to HTTPS. Set SSL/TLS to Full (strict) in Cloudflare once AutoSSL is issued.
3. www vs non-www mismatch
Check Settings → General. If WordPress Address and Site Address disagree on www, or disagree with your redirect rules, you get a loop. Make all of them consistent.
4. Plugin redirect rules
Deactivate redirect, SEO and security plugins by renaming their folders in File Manager, then test.
Clearing state while testing
Redirects are cached aggressively. Test in a private window, and clear your caching plugin and Cloudflare cache after each change, or you will keep seeing the loop after it is fixed.
