Environment: Linux; Node fetch; real ConnectReachability.layer; no database or live tunnel.
Fixture: linked tunnel, 4 ready QUIC connections. Local DNS faults affect app.t3.codes only.

=== A: public NXDOMAIN ===
Independent public DNS: {"Status":3,"TC":false,"RD":true,"RA":true,"AD":false,"CD":false,"Question":[{"name":"prod-doesnotexist-27250.t3coderelay.com","type":1}],"Authority":[{"name":"t3coderelay.com","type":6,"TTL":1800,"data":"rosemary.ns.cloudflare.com. dns.cloudflare.com. 2419954345 10000 2400 604800 1800"}]}
[07:30:48.234] ERROR (#2): 
✕ T3 Connect is NOT reachable from other devices
  The T3 Connect address is missing from public DNS. The relay did not publish it.
  Fix: Restart T3 Code. If it stays, run `t3 connect` again.
  More info: https://github.com/pingdotgg/t3code/blob/main/docs/user/t3-connect-troubleshooting.md#the-t3-connect-address-does-not-resolve-or-answer { cause: 'dns_failed' }
Classification: dns_failed
✕ T3 Connect is NOT reachable from other devices
  The T3 Connect address is missing from public DNS. The relay did not publish it.
  Fix: Restart T3 Code. If it stays, run `t3 connect` again.
  More info: https://github.com/pingdotgg/t3code/blob/main/docs/user/t3-connect-troubleshooting.md#the-t3-connect-address-does-not-resolve-or-answer

=== B: stale local not-found / public record exists ===
Independent public DNS: {"Status":0,"TC":false,"RD":true,"RA":true,"AD":false,"CD":false,"Question":[{"name":"app.t3.codes","type":1}],"Answer":[{"name":"app.t3.codes","type":5,"TTL":300,"data":"cname.vercel-dns-016.com."},{"name":"cname.vercel-dns-016.com","type":1,"TTL":300,"data":"216.150.1.129"},{"name":"cname.vercel-dns-016.com","type":1,"TTL":300,"data":"216.150.16.129"}]}
[07:30:48.327] ERROR (#35): 
✕ T3 Connect is NOT reachable from other devices
  The T3 Connect address resolves in public DNS, but this network's DNS still has an old cached answer that it does not exist.
  Fix: Wait. The cached answer usually clears within about 30 minutes.
  More info: https://github.com/pingdotgg/t3code/blob/main/docs/user/t3-connect-troubleshooting.md#the-t3-connect-address-does-not-resolve-or-answer { cause: 'dns_failed' }
Classification: dns_failed
✕ T3 Connect is NOT reachable from other devices
  The T3 Connect address resolves in public DNS, but this network's DNS still has an old cached answer that it does not exist.
  Fix: Wait. The cached answer usually clears within about 30 minutes.
  More info: https://github.com/pingdotgg/t3code/blob/main/docs/user/t3-connect-troubleshooting.md#the-t3-connect-address-does-not-resolve-or-answer

=== C: getaddrinfo EBUSY / public record exists ===
Independent public DNS: {"Status":0,"TC":false,"RD":true,"RA":true,"AD":false,"CD":false,"Question":[{"name":"app.t3.codes","type":1}],"Answer":[{"name":"app.t3.codes","type":5,"TTL":300,"data":"cname.vercel-dns-016.com."},{"name":"cname.vercel-dns-016.com","type":1,"TTL":300,"data":"216.150.1.129"},{"name":"cname.vercel-dns-016.com","type":1,"TTL":300,"data":"216.150.16.129"}]}
[07:30:48.398] ERROR (#68): 
✕ T3 Connect is NOT reachable from other devices
  The T3 Connect address resolves in public DNS, but this network's DNS still has an old cached answer that it does not exist.
  Fix: Wait. The cached answer usually clears within about 30 minutes.
  More info: https://github.com/pingdotgg/t3code/blob/main/docs/user/t3-connect-troubleshooting.md#the-t3-connect-address-does-not-resolve-or-answer { cause: 'dns_failed' }
Classification: dns_failed
✕ T3 Connect is NOT reachable from other devices
  The T3 Connect address resolves in public DNS, but this network's DNS still has an old cached answer that it does not exist.
  Fix: Wait. The cached answer usually clears within about 30 minutes.
  More info: https://github.com/pingdotgg/t3code/blob/main/docs/user/t3-connect-troubleshooting.md#the-t3-connect-address-does-not-resolve-or-answer

=== D: temporary resolver failure ===
Independent public DNS: {"Status":0,"TC":false,"RD":true,"RA":true,"AD":false,"CD":false,"Question":[{"name":"app.t3.codes","type":1}],"Answer":[{"name":"app.t3.codes","type":5,"TTL":300,"data":"cname.vercel-dns-016.com."},{"name":"cname.vercel-dns-016.com","type":1,"TTL":300,"data":"216.150.1.129"},{"name":"cname.vercel-dns-016.com","type":1,"TTL":300,"data":"216.150.16.129"}]}
[07:30:48.438] ERROR (#101): 
✕ T3 Connect is NOT reachable from other devices
  The T3 Connect address does not resolve from this machine.
  Fix: Check the DNS settings on this machine or its VPN.
  More info: https://github.com/pingdotgg/t3code/blob/main/docs/user/t3-connect-troubleshooting.md#the-t3-connect-address-does-not-resolve-or-answer { cause: 'dns_failed' }
Classification: dns_failed
✕ T3 Connect is NOT reachable from other devices
  The T3 Connect address does not resolve from this machine.
  Fix: Check the DNS settings on this machine or its VPN.
  More info: https://github.com/pingdotgg/t3code/blob/main/docs/user/t3-connect-troubleshooting.md#the-t3-connect-address-does-not-resolve-or-answer