[Minor] Fix Content-Type for DMARC reports

Issue: #1793
Closes: #1793

diff --git a/src/plugins/lua/dmarc.lua b/src/plugins/lua/dmarc.lua
index 10aa955898c4d810b101a216ea58ababf92feda4..3c2562b4cc7dbfecdbca2468850529e5e73fbbcd 100644 (file)
--- a/src/plugins/lua/dmarc.lua
+++ b/src/plugins/lua/dmarc.lua
@@ -54,7 +54,7 @@ Subject: Report Domain: %s
 Date: %s
 MIME-Version: 1.0
 Message-ID: <%s>
-Content-Type: multipart/alternative;
+Content-Type: multipart/mixed;
        boundary="----=_NextPart_000_024E_01CC9B0A.AFE54C00"
 
 This is a multipart message in MIME format.