WordPress website down with error “redirected you too many times.”

Did you update the WordPress Address (URL) and Site Address (URL) in the database or back-office ? Does it match with your wp-config.php WP_HOME and WP_SITEURL. If it still doesn’t work you can deactivate all the plugins (rename the wp-content/plugins/ folder) and reinstall them one at a time.

Source : WPBeginner