diff --git a/plugins/commands/serve/service/synced_folder_service.rb b/plugins/commands/serve/service/synced_folder_service.rb
index d0b9b509f..28487ac72 100644
--- a/plugins/commands/serve/service/synced_folder_service.rb
+++ b/plugins/commands/serve/service/synced_folder_service.rb
@@ -112,7 +112,7 @@ module VagrantPlugins
           with_plugin(ctx, plugins, broker: broker) do |plugin|
             machine, folders, opts = mapper.funcspec_map(
               req,
-              expect: [Vagrant::Machine, Folders, Type::Options]
+              expect: [Vagrant::Machine, Type::Folders, Type::Options]
             )
             # change the top level folders hash key to a string
             folders = folders.value