diff --git a/src/media/media_attribute.cpp b/src/media/media_attribute.cpp
index 50052f883d0010609cae8c415fd20953af11f135..a5c0b7f84f290f26f82ee0478521039c8b7d631f 100644
--- a/src/media/media_attribute.cpp
+++ b/src/media/media_attribute.cpp
@@ -136,7 +136,9 @@ MediaAttribute::mediaTypeToString(MediaType type)
         return libjami::Media::MediaAttributeValue::AUDIO;
     if (type == MediaType::MEDIA_VIDEO)
         return libjami::Media::MediaAttributeValue::VIDEO;
-    return nullptr;
+    if (type == MediaType::MEDIA_NONE)
+        return libjami::Media::MediaAttributeValue::SRC_TYPE_NONE;
+    return "UNKNOWN";
 }
 
 bool