Real root cause of Nextcloud "Unknown error during upload" on large files:
Traefik's default-transport responseHeaderTimeout=30s killed the chunk-assembly
MOVE (which takes >30s for multi-GB files) -> 504. Added a dedicated
nextcloud-transport (3600s) and pointed nextcloud-service at it, on both nodes.
Proven: 8GB upload MOVE now 201 @ 31.7s (was 504 @ 30.0s).
Rewrote the runbook: corrected cause (was mis-attributed to Cloudflare/DoH),
plus the hard-won gotcha on editing single-file-bind-mounted dynamic_conf
(in-place cp only; never mv; validate before write).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Full diagnosis + fix for "Unknown error during upload" on large files:
root cause is browser DNS-over-HTTPS bypassing LAN DNS -> Cloudflare mangles
the parallel chunk stream. Server/DNS already correct (Technitium+UniFi return
internal .185). Fix = disable browser DoH (.reg/PowerShell/GPO included).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>