Hello Vercel team,
We are investigating a reproducible delivery issue affecting gnezdosovy.ru / www.gnezdosovy.ru. The same site at gnezdosovy.vercel.app works over the same Russian connection without a VPN. Both hostnames work through a VPN.
Measurements on 18 September 2026:
- Apex returns its configured 308 redirect to www.
- www establishes TCP and verified TLS, returns HTTP 200, then stops delivering the body after approximately 8-21 KB.
- Main page: 20,636 / 357,286 bytes, timeout after 12 seconds. A repeat stopped at 13,562 bytes.
- vercel.app: all 357,286 bytes in approximately 0.37-0.68 seconds.
- www /menu: 13,559 / 180,129 bytes; CSS: 13,612 / 28,587; image response: 20,620 / 626,327.
- Small JS, robots.txt, HTTP 304 and an 8,192-byte range response complete.
The strongest comparison: using matching SNI/Host and pinning both names with --resolve to the SAME edge IP, vercel.app completes and www stalls. This repeats on 216.198.79.1, 64.29.17.1, 216.198.79.195 and 64.29.17.195.
Controls:
- Direct tests explicitly used the physical Ethernet interface, avoiding the active VPN route.
- HTTP/1.1 and HTTP/2 reproduce the issue; TLS 1.2/1.3 and strict certificate/hostname checks pass.
- Both hosts report the same ETag and a cache HIT; fully fetched content matches.
- gzip, a fresh query and a no-cache request did not fix it.
- DNS delegation and authoritative responses agree; domains are verified. No AAAA records or broken DNSSEC delegation were found.
- Deliberately mismatched SNI/Host returns a separate 403; that is not the failure reported here.
Could Vercel staff advise whether domain-specific edge handling or a known regional network issue could explain this, and suggest a targeted next test? We have not established whether the cause is on the edge or downstream and do not attribute it to a particular provider or filtering system.
We can provide request IDs and selected headers privately to verified Vercel staff. Please advise a suitable private channel for those details. We would prefer a diagnostic or supported remediation that does not require changing nameservers or moving the apex domain.
Thank you.