diff --git a/lib/API/JSON/v1/DynamicSegments.php b/lib/API/JSON/v1/DynamicSegments.php
index ee0819844c..809b306d89 100644
--- a/lib/API/JSON/v1/DynamicSegments.php
+++ b/lib/API/JSON/v1/DynamicSegments.php
@@ -121,22 +121,22 @@ class DynamicSegments extends APIEndpoint {
   private function getErrorString(InvalidFilterException $e) {
     switch ($e->getCode()) {
       case InvalidFilterException::MISSING_TYPE:
-        return WPFunctions::get()->__('Segment type is missing.', 'mailpoet');
+        return WPFunctions::get()->__('The segment type is missing.', 'mailpoet');
       case InvalidFilterException::INVALID_TYPE:
-        return WPFunctions::get()->__('Segment type is unknown.', 'mailpoet');
+        return WPFunctions::get()->__('The segment type is unknown.', 'mailpoet');
       case InvalidFilterException::MISSING_ROLE:
-        return WPFunctions::get()->__('Please select user role.', 'mailpoet');
+        return WPFunctions::get()->__('Please select a user role.', 'mailpoet');
       case InvalidFilterException::MISSING_ACTION:
       case InvalidFilterException::INVALID_EMAIL_ACTION:
-        return WPFunctions::get()->__('Please select email action.', 'mailpoet');
+        return WPFunctions::get()->__('Please select an email action.', 'mailpoet');
       case InvalidFilterException::MISSING_NEWSLETTER_ID:
         return WPFunctions::get()->__('Please select an email.', 'mailpoet');
       case InvalidFilterException::MISSING_PRODUCT_ID:
-        return WPFunctions::get()->__('Please select product.', 'mailpoet');
+        return WPFunctions::get()->__('Please select a product.', 'mailpoet');
       case InvalidFilterException::MISSING_COUNTRY:
-        return WPFunctions::get()->__('Please select country.', 'mailpoet');
+        return WPFunctions::get()->__('Please select a country.', 'mailpoet');
       case InvalidFilterException::MISSING_CATEGORY_ID:
-        return WPFunctions::get()->__('Please select category.', 'mailpoet');
+        return WPFunctions::get()->__('Please select a category.', 'mailpoet');
       case InvalidFilterException::MISSING_VALUE:
         return WPFunctions::get()->__('Please fill all required values.', 'mailpoet');
       case InvalidFilterException::MISSING_NUMBER_OF_ORDERS_FIELDS:
diff --git a/tests/integration/API/JSON/v1/DynamicSegmentsTest.php b/tests/integration/API/JSON/v1/DynamicSegmentsTest.php
index 2b228fe624..4c370cffb3 100644
--- a/tests/integration/API/JSON/v1/DynamicSegmentsTest.php
+++ b/tests/integration/API/JSON/v1/DynamicSegmentsTest.php
@@ -56,7 +56,7 @@ class DynamicSegmentsTest extends \MailPoetTest {
     ]);
     expect($response)->isInstanceOf('\MailPoet\API\JSON\ErrorResponse');
     expect($response->status)->equals(self::INVALID_DATA_RESPONSE_CODE);
-    expect($response->errors[0]['message'])->equals('Segment type is missing.');
+    expect($response->errors[0]['message'])->equals('The segment type is missing.');
   }
 
   public function testSaverReturnsErrorOnDuplicateRecord() {