Update tranlation text domain

inc/helpers/validation-rules/class-unique.php

@@ -78,7 +78,7 @@ class Unique extends Rule {
 		* Customize the error message for the customer.
 		*/
 		if (in_array($model, $user_models, true)) {
-			$this->message = __('A customer with the same email address or username already exists.', 'wp-ultimo');
+			$this->message = __('A customer with the same email address or username already exists.', 'wp-multisite-waas');
 		}
 
 		if ( ! $existing) {