update catch block to prevent situation where error is undefined

Author: DominicH247

docker/sync-wrap/src/handlers.js

@@ -514,7 +514,8 @@ async function proxy(req, res, next) {
             await send_response(response.statusCode, {headers: headers, response: response});
         })
         .catch(async (fin) => {
-            await send_response(fin.error === "timeout" ? 504 : 502, {headers: headers, error: fin.error});
+            const error = fin.error ? fin.error : fin;
+            await send_response(fin.error === "timeout" ? 504 : 502, {headers: headers, error});
         });
 
 }