Merged in feature/MAW-855-import-code-into-aws (pull request #2)

code import from pantheon

* code import from pantheon

wp/wp-content/plugins/wp-mail-smtp/src/Admin/DomainChecker.php

@@ -2,6 +2,8 @@
 
 namespace WPMailSMTP\Admin;
 
+use WPMailSMTP\Helpers\Helpers;
+
 /**
  * Class for interacting with the Domain Checker API.
  *
@@ -53,7 +55,12 @@ class DomainChecker {
 			'domain' => $sending_domain,
 		];
 
-		$response = wp_remote_get( add_query_arg( $params, self::ENDPOINT ) );
+		$response = wp_remote_get(
+			add_query_arg( $params, self::ENDPOINT ),
+			[
+				'user-agent' => Helpers::get_default_user_agent(),
+			]
+		);
 
 		if ( is_wp_error( $response ) ) {
 			$this->results = [