Too Many Redirects Error When Accessing wp-admin

Symptoms

When trying to access wp-admin from your WordPress site, you get a "Too Many Redirects" error.

Solution

To fix this error, you can add the following code to the top of the wp-config.php file:

if (strpos($_SERVER['HTTP_X_FORWARDED_PROTO'], 'https') !== false)
   $_SERVER['HTTPS']='on';