Getting 404 on POST /hook for GitHub, using Helm chart, behind Traefik v2

I am running the Helm chart, on GKE, with Traefik v2 as a load balancer.

I am seeing a:
“POST /hook HTTP/1.1” 404 19 “-” “-” 486 - - 0ms
from Traefik, for every new push to a repository enabled in Drone.

I see nothing in Drone logs - even with debug enabled.

My configuration can be seen at https://github.com/MikaelElkiaer/flux-get-started

Hoping that someone has experienced similar and can point me in the right direction.

Could it be that GitHub calls /hook via http, and not https?
I get a 404 if I try to POST to /hook via http, but it works fine with https.

Yes, this is possible if you did not set DRONE_SERVER_PROTO=https. The DRONE_SERVER_HOST and DRONE_SERVER_PROTO fields are what allows Drone to know its own public URL which is used to create webhooks and perform redirects.

Eurekah!

I had recently added server.protocol=https, but evidently it had not been applied (using FluxCD and Helm - quite a few places where it can go wrong).
But now I just removed my drone service and dependencies, re-added them, and it works.