diff --git a/boards/models/attachment/viewers.py b/boards/models/attachment/viewers.py
--- a/boards/models/attachment/viewers.py
+++ b/boards/models/attachment/viewers.py
@@ -27,7 +27,7 @@ FILE_TYPES_VIDEO = (
 FILE_TYPE_SVG = 'image/svg'
 FILE_TYPES_AUDIO = (
     'audio/ogg',
-    'audio/mp3',
+    'audio/mpeg',
     'audio/opus',
     'audio/x-flac',
     'audio/mpeg',