diff --git a/tests/ConvertKitAPITest.php b/tests/ConvertKitAPITest.php
index bf2ea2f..b6f6aa5 100644
--- a/tests/ConvertKitAPITest.php
+++ b/tests/ConvertKitAPITest.php
@@ -4060,6 +4060,9 @@ public function testUnsubscribeByEmail()
             email_address: $emailAddress
         );
 
+        // Wait a moment to ensure subscriber is created.
+        sleep(3);
+
         // Unsubscribe.
         $this->assertNull($this->api->unsubscribe_by_email($emailAddress));
     }
@@ -4107,6 +4110,9 @@ public function testUnsubscribe()
             email_address: $emailAddress
         );
 
+        // Wait a moment to ensure subscriber is created.
+        sleep(3);
+
         // Unsubscribe.
         $this->assertNull($this->api->unsubscribe($result->subscriber->id));
     }