diff --git a/src/Adapter/Guzzle.php b/src/Adapter/Guzzle.php
index a7d8ad1c..08c7584e 100644
--- a/src/Adapter/Guzzle.php
+++ b/src/Adapter/Guzzle.php
@@ -92,7 +92,14 @@ public function request(string $method, string $uri, array $data = [], array $he
 
     private function checkError(ResponseInterface $response)
     {
-        $json = json_decode($response->getBody());
+        $body = (string) $response->getBody();
+
+        // If first character of the response body is not { then the response is in plain text so need to skip below checks as they fail.
+        if (strpos($body, '{') !== 0) {
+            return;
+        }
+
+        $json = json_decode($body);
 
         if (json_last_error() !== JSON_ERROR_NONE) {
             throw new JSONException();