symfony
diff --git a/‎src/Symfony/Component/HttpClient/CurlHttpClient.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/HttpClient/CurlHttpClient.php
+3-2Lines changed: 3 additions & 2 deletions b/‎src/Symfony/Component/HttpClient/CurlHttpClient.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/HttpClient/CurlHttpClient.php
+3-2Lines changed: 3 additions & 2 deletions
diff --git a/‎src/Symfony/Component/Mailer/Bridge/Mailgun/Transport/MailgunHttpTransport.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Mailer/Bridge/Mailgun/Transport/MailgunHttpTransport.php
+1Lines changed: 1 addition & 0 deletions b/‎src/Symfony/Component/Mailer/Bridge/Mailgun/Transport/MailgunHttpTransport.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Mailer/Bridge/Mailgun/Transport/MailgunHttpTransport.php
+1Lines changed: 1 addition & 0 deletions
@@ -246,8 +246,9 @@ public function request(string $method, string $url, array $options = []): Respo
 
             if (isset($options['normalized_headers']['content-length'][0])) {
                 $curlopts[\CURLOPT_INFILESIZE] = (int) substr($options['normalized_headers']['content-length'][0], \strlen('Content-Length: '));
-            } elseif (!isset($options['normalized_headers']['transfer-encoding'])) {
-                $curlopts[\CURLOPT_INFILESIZE] = -1;
+            }
+            if (!isset($options['normalized_headers']['transfer-encoding'])) {
+                $curlopts[\CURLOPT_HTTPHEADER][] = 'Transfer-Encoding:'.(isset($curlopts[\CURLOPT_INFILESIZE]) ? '' : ' chunked');
             }
 
             if ('POST' !== $method) {
 
@@ -63,6 +63,7 @@ protected function doSendHttp(SentMessage $message): ResponseInterface
 
         $endpoint = sprintf('%s/v3/%s/messages.mime', $this->getEndpoint(), urlencode($this->domain));
         $response = $this->client->request('POST', 'https://'.$endpoint, [
+            'http_version' => '1.1',
             'auth_basic' => 'api:'.$this->key,
             'headers' => $headers,
             'body' => $body->bodyToIterable(),