Railway error deploying my server with nodejs saying hostname: 'undefined'?

Question

This is on theRailway console:

original: Error: getaddrinfo ENOTFOUND undefined
original: Error: getaddrinfo ENOTFOUND undefined
at GetAddrInfoReqWrap.onlookup [as oncomplete] (node:dns:109:26) {
at GetAddrInfoReqWrap.onlookup [as oncomplete] (node:dns:109:26) {
errno: -3008,
errno: -3008,
code: 'ENOTFOUND',
code: 'ENOTFOUND',
syscall: 'getaddrinfo',
syscall: 'getaddrinfo',
hostname: 'undefined'
hostname: 'undefined'

I follow all the steps to deploy my full-stack app on railway. I first, deployed my db from postgress successfully and pass it the links to my .env on my server side app. Now, looks like the hostname is not working not sure why is this happening.