diff --git a/lib/messagebus/mailer.rb b/lib/messagebus/mailer.rb
index dc56c634a11ea8e766fa3471b7692466e0e2fefb..6ad43ab1864f34169ea3945a50981d85a38039ee 100644
--- a/lib/messagebus/mailer.rb
+++ b/lib/messagebus/mailer.rb
@@ -20,6 +20,9 @@ module Messagebus
     if message.multipart?
       msg[:plaintextBody] = message.text_part.body.to_s if message.text_part
       msg[:htmlBody] = message.html_part.body.to_s if message.html_part
+    else
+      msg[:plaintextBody] = message.body.to_s
+      msg[:htmlBody] = message.body.to_s
     end
 
     begin