diff --git a/src/Http/Transport/CurlTransport.php b/src/Http/Transport/CurlTransport.php
index 8f537677..7336510f 100644
--- a/src/Http/Transport/CurlTransport.php
+++ b/src/Http/Transport/CurlTransport.php
@@ -111,7 +111,7 @@ public function request(TransportRequest $request): TransportResponse
             throw new NetworkException('Bad response.', $httpCode);
         }
 
-        curl_close($ch);
+        unset($ch); // close curl handle
 
         $sessionId = null;
         if (isset($headers['set-cookie'])) {