A redirect loop is a configuration error in which URL A redirects to URL B, and URL B redirects back to URL A — or through a longer circular chain — so that no final destination is ever reached. Browsers typically detect the loop after a small number of iterations and display an error such as “Too many redirects” or ERR_TOO_MANY_REDIRECTS. For search engines, a looping URL is effectively uncrawlable: Googlebot will abandon it and the page will not be indexed. Redirect loops most often occur when HTTPS migration rules conflict with existing HTTP redirects, when CDN or proxy rules interact unexpectedly with server-level htaccess directives, or during CMS migrations where both old and new routing logic are simultaneously active. They are diagnosed quickly using browser developer tools or dedicated redirect-checker utilities.