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. 2419954355 10000 2400 604800 1800"}]}
[07:30:57.256] ERROR (#2): 
✕ 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

=== 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":"216.150.1.1"},{"name":"cname.vercel-dns-016.com","type":1,"TTL":300,"data":"216.150.16.1"}]}
[07:30:57.330] ERROR (#31): 
✕ 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

=== 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":"216.150.16.1"},{"name":"cname.vercel-dns-016.com","type":1,"TTL":300,"data":"216.150.1.1"}]}
[07:30:57.366] ERROR (#60): 
✕ T3 Connect is NOT reachable from other devices
  The T3 Connect address did not answer from this machine.
  Fix: Check the network, VPN, or proxy on this machine.
  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: 'timeout' }
Classification: timeout
✕ T3 Connect is NOT reachable from other devices
  The T3 Connect address did not answer from this machine.
  Fix: Check the network, VPN, or proxy on this machine.
  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":"216.150.16.1"},{"name":"cname.vercel-dns-016.com","type":1,"TTL":300,"data":"216.150.1.1"}]}
[07:30:57.400] ERROR (#89): 
✕ 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