diff --git a/src/Plugin/ImageAPIOptimizeProcessor/ReSmushit.php b/src/Plugin/ImageAPIOptimizeProcessor/ReSmushit.php
index ab4bc26..51cca27 100644
--- a/src/Plugin/ImageAPIOptimizeProcessor/ReSmushit.php
+++ b/src/Plugin/ImageAPIOptimizeProcessor/ReSmushit.php
@@ -69,7 +69,7 @@ final class ReSmushit extends ConfigurableImageAPIOptimizeProcessorBase {
     }
 
     try {
-      $response = $this->httpClient->post('http://api.resmush.it/ws.php', ['multipart' => $fields]);
+      $response = $this->httpClient->post('https://api.resmush.it/ws.php', ['multipart' => $fields]);
       $body = $response->getBody();
       $json = json_decode($body);