Specific website media/video fails on home WiFi but works instantly on 5G + VPN. ISP/CDN routing issue?

[u/meetyoutoo]

Specific website media/video fails on home WiFi/cabled connection but works instantly on 5G + VPN. ISP/CDN routing issue?

I’m trying to troubleshoot a weird networking issue and I’m running out of ideas.

Problem:
A specific website loads normally on my home WiFi, but the actual media/video content fails to load. I get:

> “The media could not be loaded, either because the server or network failed or because the format is not supported.”

What’s strange:
- Works perfectly on 5G
- Works perfectly when using VPN over the same WiFi
- Website itself loads fine on WiFi
- Only the media stream/content fails
- Multiple browsers tested on iPhone and browsers
- No recent router/network changes

Diagnostics from the site:
- JS/player endpoints return 200 OK
- Actual media responses show “Resp: 0”
- Looks like media segments never arrive

Things I already tested:
- Changed DNS to Cloudflare (1.1.1.1)
- Tested with VPN ON over WiFi (works instantly)
- Ran IPv6 tests (9/10, no major issues)
- Disabled/checked common iPhone privacy settings
- Tested multiple browsers
- No obvious adblockers interfering
- WiFi itself is stable and fast

Current theory:
This feels more like:
- ISP peering/routing issue
- CDN edge issue
- IP reputation/rate limiting
- TLS/CDN transport issue
- Possibly ISP path to media CDN specifically

Since VPN fixes it immediately, I assume the endpoint itself is fine and only the route from my ISP/public IP is problematic.

Has anyone seen similar behavior where:
- website loads
- media fails
- VPN fixes everything instantly

Any ideas for deeper diagnostics I can run before escalating further with ISP?

If this isn’t the right subreddit for it, my sincerest apologies and please do show me the way to the proper one.

[u/Turbulent-Metal-6287]

The issue form your isp side
Try install ipv4 extension on your browser and visti the site with your vpn and see the IPs that response and then try without vpn and you will see somthing missing also try to take packet capture and send it to your isp support so they can see what they missing
I think the issue thats some of CDNs domains of the website not reached by your isp route or dns