Why this happens

This happens when your site's URL settings, SSL configuration, or a caching/redirect plugin create a loop - for example, your site tries to redirect HTTP to HTTPS, but a setting somewhere redirects it back to HTTP again, and the browser gives up after too many redirect attempts.

Step-by-step fix

  1. Go to wp-admin > Settings > General and check that both the WordPress Address (URL) and Site Address (URL) use the same protocol (https://).
  2. If an SSL or caching plugin is installed (like Really Simple SSL), temporarily disable it.
  3. Clear your browser cookies and cache, then try again.
  4. If you're using Cloudflare, set the SSL mode to 'Full' or 'Full (Strict)', not 'Flexible'.

How to prevent it happening again