diff --git a/config/routes.rb b/config/routes.rb
index 51fdf47c..2c906b69 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -186,8 +186,10 @@ if Redmine::Plugin.installed? 'redmine_dmsf'
 
     # WebDAV workaround for clients checking WebDAV availability in the root
     unless Redmine::Plugin.installed?('easy_extensions')
-      match '/', to: ->(env) { [405, {}, [env.to_s]] }, via: %i[propfind options]
+      match '/', to: ->(env) { [405, {}, ["#{env['REQUEST_METHOD']} method is not allowed"]] },
+            via: %i[propfind options]
     end
-    match '/dmsf', to: ->(env) { [405, {}, [env.to_s]] }, via: %i[propfind options]
+    match '/dmsf', to: ->(env) { [405, {}, ["#{env['REQUEST_METHOD']} method is not allowed"]] },
+          via: %i[propfind options]
   end
 end