Performance Issue & CloudFlare error

1) Trying to a run performance scan, and getting the following message:

The performance test didn’t return any results. This probably means you’re on a local website (which we can’t scan) or something went wrong trying to access WPMU DEV. Try again and if this error continues to appear please open a ticket with our support heroes

2) Getting fatal error in the Browser Caching page, under Hummigbird > Caching > Browser Caching

Catchable fatal error: Object of class WP_Error could not be converted to string in /xxx/wp-includes/general-template.php on line 4232

Warning: explode() expects parameter 2 to be string, array given in /xxxx/wp-content/plugins/wp-hummingbird/core/modules/class-module-caching.php on line 183