your web app which is hosted in heroku had been broken kindly check it.i think heroku going to stop its free services so it deletes the inactive accounts present there.so may be that is the problem
] RangeError [ERR_HTTP_INVALID_STATUS_CODE]: Invalid status code: undefined
[0] at new NodeError (node:internal/errors:405:5)
[0] at ServerResponse.writeHead (node:_http_server:347:11)
[0] at ServerResponse._implicitHeader (node:http_server:338:8)
[0] at write (node:_http_outgoing:915:9)
[0] at ServerResponse.end (node:_http_outgoing:1026:5)
[0] at ServerResponse.send (D:\flipkart-mern-master\node_modules\express\lib\response.js:232:10)
[0] at ServerResponse.json (D:\flipkart-mern-master\node_modules\express\lib\response.js:278:15)
[0] at module.exports (D:\flipkart-mern-master\backend\middlewares\error.js:31:32)
[0] at Layer.handle_error (D:\flipkart-mern-master\node_modules\express\lib\router\layer.js:71:5)
[0] at trim_prefix (D:\flipkart-mern-master\node_modules\express\lib\router\index.js:326:13)