WebSockets do not work on Custom domain?

I am currently adding websockets to my server but came to a very strange discovery, The websockets Immediately close before connecting when i use my Custom domain, the project.glitch.me domain however works perfectly fine. I am using the Express-ws package (I have very Complex routers). Is there some special handeling or forwarding I need to do to get this working?

DNS hosting is Namecheap if it’s something i have to do with the dns

Could you share a project link, expected behavior, some logs and maybe some code? If it’s “very complex rout[ing]” it might take a while for someone else to understand it, and it’ll be faster if you show them code where you suspect the error is.

I’ve worked with a little websockets with nodejs previously.

When s2sl was being worked on, we used os.js which used websockets, I’ll see if I can find out a reason why websockets didn’t work

looks like there hasn’t been a solution for it yet, if you use cloudflare you might have issues with websockets
I’m actually confused cloudflare says it should work

maybe the fly.io proxy doesn’t work with websockets?

router.ws is defined elsewhere using express-ws package

const api = require("express").Router();
    api.ws("/Echo", (ws,req)=>{
      console.log("Connection Opening")
      ws.on("message", function (msg){
      ws.on('close', () => {
            console.log('WebSocket was closed')
module properly exported later

Test Cases with Logging:

WS: connect ws://MyDomain/path/Echo
Connection Opening
WebSocket was Closed
WS: Test - timeout
WS: Test - timeout
WS: It Works - timeout

WS: connect ws://project.glitch.me/path/Echo
Connection Opening
WS: Test
WS: Test
WS: It Works
It Works

Also the DNS host is Namecheap

I also have this problem, my domain registar is Google Domains. No matter how I try, no custom domain, websockets work great, but with the custom domain, websockets don’t work.