iPhone Safari Intermittently Can't Resolve Railway Custom Domain
poll20
HOBBYOP

14 days ago

Hi Railway team,

I'm facing an intermittent connectivity/DNS issue with my Railway backend custom domain, specifically on iPhone.

Backend custom domain:

api.lewkout.com

Railway CNAME target:

7558jhs1.up.railway.app

DNS provider:

Hostinger

The issue is reproducible on an iPhone using mobile data.

Sometimes the API works normally and returns JSON:

https://api.lewkout.com/categories?page=1

But most of the time, Safari shows:

"Safari can't open the page because the server can't be found."

When this happens, my frontend also fails to load API data, and I don't see the /categories request reaching my Railway service logs.

The same endpoint works normally on Android.

I also tested disabling "Limit IP Address Tracking" on the iPhone. The API started working temporarily, but later the same issue occurred again even with that setting disabled.

Railway shows api.lewkout.com as verified with a green check, and the Hostinger DNS CNAME record matches the Railway-provided target.

This appears to be an intermittent DNS/network resolution issue before the request reaches my Railway service.

Could someone please help me investigate whether this could be related to Railway custom domain DNS, routing, IPv6, or iPhone/iOS network compatibility?

I can provide screenshots of the Railway custom domain configuration, Hostinger DNS records if needed.

Thanks!

$10 Bounty

6 Replies

Railway
BOT

14 days ago

This thread has been opened as a bounty so the community can help solve it.

Status changed to Open Railway 14 days ago


Try setting your device's DNS to use 1.1.1.1, or try using a VPN.


0x5b62656e5d

Try setting your device's DNS to use `1.1.1.1`, or try using a VPN.

poll20
HOBBYOP

14 days ago

hey thanks for reply. The Cloudflare 1.1.1.1 app is not available in my App Store country/region (India).

I'm testing on iPhone using cellular/mobile data, so I can't manually set 1.1.1.1 DNS through the normal iOS Wi-Fi DNS settings.

Would testing with a regular VPN be sufficient?


Some Indian ISPs (eg, Jio) have been known to block traffic to Railway's domains and/or servers, so yes, try using a VPN to access the site.


poll20
HOBBYOP

14 days ago

I tested it with a VPN on the same iPhone and the issue disappears completely.

With VPN ON:

With VPN OFF on the same iPhone/mobile network:

  • Safari intermittently says "server can't be found".
  • The API request does not appear to reach my Railway service.

So the issue seems to be related to DNS/network resolution or routing on the normal mobile network path.

Please let me know what else I can test or provide to help investigate this.


Unfortunately, as I mentioned above, it seems like the ISP is blocking traffic to Railway's edge/servers.

There isn't anything Railway can do about that, and the only thing you can do is to use a VPN to access your websites until your ISP lifts the block.


poll20
HOBBYOP

14 days ago

Got it, thanks for helping me identify the issue. Since this is a customer-facing production website, using a VPN isn't practical for the users.

I'll try putting the custom API domain behind Cloudflare proxy as a workaround and test whether that resolves the ISP routing/blocking issue.

Thanks again for your help!


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