Investigate missing telemetry from the Flå box

Investigate why Flå remains kaukus_box_telemetry_up=0 after operator telemetry-key approval, unlike other boxes. Read-only production diagnosis first; do not change services, credentials, configuration or deploy without agreement. Acceptance: identify Flå's box identity and provisioner version, distinguish absent publications from rejected/stale samples, correlate router/NATS/agent evidence and provide an evidence-backed cause and next action. Verify any authorized correction with fresh accepted telemetry. Verified diagnosis (2026-10-30 13:18 UTC): user corrected SSH login to mathias@router.kaukus.no; configured-agent SSH and read-only sudo inspection succeeded. Flå is box f86f3b2561fa4f868136aa794db2b909, room fla, provisioner 1.2.0, applied configuration, approved telemetry identity matching the announced key. Router logs show 'invalid telemetry sample' approximately every 30 seconds, after the authentication/decryption stage. Stored announcements show clock_offset_secs=123 (box behind), ntp_enabled=true, synchronized=false, custom_servers=[no.pool.ntp.org]. Other five reporting boxes have offset 0 and synchronized=true. Router timedatectl confirms NTP=yes and NTPSynchronized=yes. Live router /metrics confirms all five other approved boxes telemetry_up=1 and Flå=0, with no accepted-sample timestamp for Flå. Source validates sample age <=90 seconds, so the 123-second clock lag explains rejection; key approval and transport are working. User-confirmed recovery: switched Flå to manual time and telemetry works again. This corroborates clock skew as the cause; recovery was reported by the user, not independently rechecked. User will contact local IT for a reachable NTP server. Manual time is temporary because drift can exceed the freshness window again. Public alternative suggested: time.cloudflare.com, still requiring outbound UDP/123. NTP network reachability/failure reason remains unverified. No correction was performed by the assistant. Do not loosen the freshness/authentication checks or reprovision the key. Warnings are in cloud-router container logs, not an agent publication failure. No repository or production state changes made.