diff --git a/lib/utils/mu-error.hh b/lib/utils/mu-error.hh
index 42600862..b2d6ed24 100644
--- a/lib/utils/mu-error.hh
+++ b/lib/utils/mu-error.hh
@@ -36,6 +36,7 @@ struct Error final: public std::exception {
                 Index,
                 Internal,
                 InvalidArgument,
+                Message,
                 NotFound,
                 Parsing,
                 Query,