the site's working fine for me (although I am getting "Cannot GET /api/v1" on that endpoint but that just means there's nothing on that endpoint)

How you checked it ?
Can you try accessing this URL
https://pos-system-backend-production.up.railway.app/api/v1/parcel/getParcel?hotelUser=6628eff62a4f70c2b7ec7c50

Sure, it's returning

{"success":true,"message":"Parcel retrieved successfully","data":{"_id":"6742c4613b5bac1d147a7225","hotelUser":"6628eff62a4f70c2b7ec7c50","items":[],"__v":0}}

if it's not working for you then it could be that you're behind a local firewall (meaning your router or ISP or something like that) could be blocking requests

I have attached screenshot below can you check it. Why I'm not able to acces the URL then ?? what might be the case

It's possible that you're behind a local firewall, meaning requests are blocked on a router or ISP level

How can I solve or troubleshoot this problem

try accessing from other devices, then if that doesn't work try connecting from a network other than your home network, and if it still doesn't work then try connecting from a network on a different ISP (you can use a VPN to aid with testing)

Okay Thank you!

No problem, best of luck!