diff --git a/mailpoet/lib/Cron/Workers/KeyCheck/PremiumKeyCheck.php b/mailpoet/lib/Cron/Workers/KeyCheck/PremiumKeyCheck.php
index a983508867..71accea43e 100644
--- a/mailpoet/lib/Cron/Workers/KeyCheck/PremiumKeyCheck.php
+++ b/mailpoet/lib/Cron/Workers/KeyCheck/PremiumKeyCheck.php
@@ -3,6 +3,7 @@
 namespace MailPoet\Cron\Workers\KeyCheck;
 
 use MailPoet\Cron\CronWorkerScheduler;
+use MailPoet\InvalidStateException;
 use MailPoet\Services\Bridge;
 use MailPoet\Settings\SettingsController;
 
@@ -26,7 +27,9 @@ class PremiumKeyCheck extends KeyCheckWorker {
 
   public function checkKey() {
     // for phpstan because we set bridge property in the init function
-    if (!$this->bridge) return;
+    if (!$this->bridge) {
+      throw new InvalidStateException('The class was not initialized properly. Please call the Init method before.');
+    };
 
     $premiumKey = $this->settings->get(Bridge::PREMIUM_KEY_SETTING_NAME);
     $result = $this->bridge->checkPremiumKey($premiumKey);
diff --git a/mailpoet/lib/Cron/Workers/KeyCheck/SendingServiceKeyCheck.php b/mailpoet/lib/Cron/Workers/KeyCheck/SendingServiceKeyCheck.php
index ceb4874ca2..d397e2bd12 100644
--- a/mailpoet/lib/Cron/Workers/KeyCheck/SendingServiceKeyCheck.php
+++ b/mailpoet/lib/Cron/Workers/KeyCheck/SendingServiceKeyCheck.php
@@ -4,6 +4,7 @@ namespace MailPoet\Cron\Workers\KeyCheck;
 
 use MailPoet\Config\ServicesChecker;
 use MailPoet\Cron\CronWorkerScheduler;
+use MailPoet\InvalidStateException;
 use MailPoet\Mailer\Mailer;
 use MailPoet\Mailer\MailerLog;
 use MailPoet\Services\Bridge;
@@ -47,7 +48,9 @@ class SendingServiceKeyCheck extends KeyCheckWorker {
 
   public function checkKey() {
     // for phpstan because we set bridge property in the init function
-    if (!$this->bridge) return;
+    if (!$this->bridge) {
+      throw new InvalidStateException('The class was not initialized properly. Please call the Init method before.');
+    };
 
     $wasPendingApproval = $this->servicesChecker->isMailPoetAPIKeyPendingApproval();