diff --git a/server/index.ts b/server/index.ts
index f1d7104..6995c05 100644
--- a/server/index.ts
+++ b/server/index.ts
@@ -189,8 +189,8 @@ app.get(`${basePrefix ? basePrefix : ''}/env.js`, (_, res) => {
       LOGIN_URL: ${JSON.stringify(LOGIN_URL) || '"check envs"'},
       LOGOUT_URL: ${JSON.stringify(LOGOUT_URL) || '"check envs"'},
       LOGIN_USERNAME_FIELD: ${JSON.stringify(LOGIN_USERNAME_FIELD) || '"check envs"'},
-      REMOVE_BACKLINK: ${!!REMOVE_BACKLINK ? REMOVE_BACKLINK.toString().toLowerCase() : '"false"'},
-      REMOVE_BACKLINK_TEXT: ${!!REMOVE_BACKLINK_TEXT ? REMOVE_BACKLINK_TEXT.toString().toLowerCase() : '"false"'}
+      REMOVE_BACKLINK: ${!!REMOVE_BACKLINK ? REMOVE_BACKLINK?.toString().toLowerCase() : '"false"'},
+      REMOVE_BACKLINK_TEXT: ${!!REMOVE_BACKLINK_TEXT ? REMOVE_BACKLINK_TEXT?.toString().toLowerCase() : '"false"'}
     }
     `,
   )