diff --git a/dmarcreceiver/commands.py b/dmarcreceiver/commands.py
index 4aee49d..48668df 100644
--- a/dmarcreceiver/commands.py
+++ b/dmarcreceiver/commands.py
@@ -122,6 +122,10 @@ def receive_report(args):
     for part in msg.walk():
         # check for zip file
         content_type = part['content-type']
+
+        if content_type is None:
+            continue
+
         if content_type.find(';') != -1:
             content_type = content_type.split(';',1)[0]