diff --git a/lib/API/JSON/v1/Services.php b/lib/API/JSON/v1/Services.php
index 81f28b87d8..4211aad046 100644
--- a/lib/API/JSON/v1/Services.php
+++ b/lib/API/JSON/v1/Services.php
@@ -89,7 +89,7 @@ class Services extends APIEndpoint {
 
     $successMessage = null;
     if ($state == Bridge::KEY_VALID) {
-      $successMessage = WPFunctions::get()->__('Your MailPoet Sending Service key has been successfully validated.', 'mailpoet');
+      $successMessage = WPFunctions::get()->__('Your MailPoet Sending Service key has been successfully validated', 'mailpoet');
     } elseif ($state == Bridge::KEY_EXPIRING) {
       $successMessage = sprintf(
         WPFunctions::get()->__('Your MailPoet Sending Service key expires on %s!', 'mailpoet'),
@@ -107,10 +107,10 @@ class Services extends APIEndpoint {
 
     switch ($state) {
       case Bridge::KEY_INVALID:
-        $error = WPFunctions::get()->__('Your MailPoet Sending Service key is invalid.', 'mailpoet');
+        $error = WPFunctions::get()->__('Your key is not valid for the MailPoet Sending Service', 'mailpoet');
         break;
       case Bridge::KEY_ALREADY_USED:
-        $error = WPFunctions::get()->__('Your MailPoet Sending Service key is already used on another site.', 'mailpoet');
+        $error = WPFunctions::get()->__('Your MailPoet Sending Service key is already used on another site', 'mailpoet');
         break;
       default:
         $code = !empty($result['code']) ? $result['code'] : Bridge::CHECK_ERROR_UNKNOWN;
@@ -151,10 +151,10 @@ class Services extends APIEndpoint {
 
     $successMessage = null;
     if ($state == Bridge::KEY_VALID) {
-      $successMessage = WPFunctions::get()->__('Your Premium key has been successfully validated.', 'mailpoet');
+      $successMessage = WPFunctions::get()->__('Your Premium key has been successfully validated', 'mailpoet');
     } elseif ($state == Bridge::KEY_EXPIRING) {
       $successMessage = sprintf(
-        WPFunctions::get()->__('Your Premium key expires on %s.', 'mailpoet'),
+        WPFunctions::get()->__('Your Premium key expires on %s', 'mailpoet'),
         $this->dateTime->formatDate(strtotime($result['data']['expire_at']))
       );
     }
@@ -172,10 +172,10 @@ class Services extends APIEndpoint {
 
     switch ($state) {
       case Bridge::KEY_INVALID:
-        $error = WPFunctions::get()->__('Your Premium key is invalid.', 'mailpoet');
+        $error = WPFunctions::get()->__('Your key is not valid for MailPoet Premium', 'mailpoet');
         break;
       case Bridge::KEY_ALREADY_USED:
-        $error = WPFunctions::get()->__('Your Premium key is already used on another site.', 'mailpoet');
+        $error = WPFunctions::get()->__('Your Premium key is already used on another site', 'mailpoet');
         break;
       default:
         $code = !empty($result['code']) ? $result['code'] : Bridge::CHECK_ERROR_UNKNOWN;
diff --git a/tests/acceptance/AddSendingKeyCest.php b/tests/acceptance/AddSendingKeyCest.php
index 59f82d7a5f..e08f6df314 100644
--- a/tests/acceptance/AddSendingKeyCest.php
+++ b/tests/acceptance/AddSendingKeyCest.php
@@ -38,8 +38,8 @@ class AddSendingKeyCest {
     // try invalid key
     $i->fillField(['name' => 'premium[premium_key]'], 'invalid-key');
     $i->click('Verify');
-    $i->waitForText('Your MailPoet Sending Service key is invalid.');
-    $i->waitForText('Your Premium key is invalid.');
+    $i->waitForText('Your key is not valid for the MailPoet Sending Service');
+    $i->waitForText('Your key is not valid for MailPoet Premium');
   }
 
   public function installAndActivatePremiumPlugin(\AcceptanceTester $i, Scenario $scenario) {