diff --git a/ext/curl/gstcurlsmtpsink.c b/ext/curl/gstcurlsmtpsink.c
index 690c4ab9502779432e791bb15bec747b28f21386..612594c383659b6ea217a4e4cbfe061602047164 100644
--- a/ext/curl/gstcurlsmtpsink.c
+++ b/ext/curl/gstcurlsmtpsink.c
@@ -635,7 +635,7 @@ gst_curl_smtp_sink_set_transfer_options_unlocked (GstCurlBaseSink * bcsink)
 
   /* time */
   date = g_date_time_new_now_local ();
-  date_str = g_date_time_format (date, "%a %b %e %H:%M:%S %Y %z");
+  date_str = g_date_time_format (date, "%a, %e %b %Y %H:%M:%S %z");
   g_date_time_unref (date);
 
   /* recipient, sender and subject are all UTF-8 strings, which are additionally