private function checkAvailability() {
		// Get the boldgrid_available transient.
		$available = get_site_transient( 'boldgrid_available' );

		// No transient was found.
		$wp_http = new WP_Http();
		$url = $this->getUrl();

		// Check that calling server is not blocked locally.
		if ( $wp_http->block_request( $url ) === false ) {
			$available = 1;
		}

		// Update the boldgrid_available transient.
		set_site_transient( 'boldgrid_available', ( int ) $available, 2 * MINUTE_IN_SECONDS );

		return $available;
	}