My internal URLs don't seem to be working anymore

Question

As of last night I noticed that my internal private URLs aren't working anymore. I have a Node app that has private internal URLs to access a Browerless and Postgres instance in my service, but I'm seeing errors such as
```
node:internal/process/promises:288
triggerUncaughtException(err, true /* fromPromise */);
^
Error: getaddrinfo ENOTFOUND postgres.railway.internal
at GetAddrInfoReqWrap.onlookup [as oncomplete] (node:dns:108:26) {
errno: -3008,
code: 'ENOTFOUND',
syscall: 'getaddrinfo',
hostname: 'postgres.railway.internal'
}
Node.js v18.18.2
```

I haven't touched this service in weeks, so not sure what changed last night.