diff --git a/server/routes.js b/server/routes.js
index 1c4a7a27..f5d1ace0 100644
--- a/server/routes.js
+++ b/server/routes.js
@@ -21,7 +21,7 @@ function initRoutes(app, wss, config) {
         return;
     }
 
-    if (config.mode !== 'omnireader' && config.mode !== 'liberama')
+    if (config.mode !== 'reader' && config.mode !== 'omnireader' && config.mode !== 'liberama')
         throw new Error(`Unknown server mode: ${config.mode}`);
 
     initStatic(app, config);