Nginx reverse proxy causes 404 on /

Summary

When reverse proxying Mattermost through nginx with the recommended config in the docs, I get a 404 on “/”. This seems to be a problem with Mattermost rather than nginx, see error message below.

Steps to reproduce

I am using Arch Linux
nginx 1.16.0-1
mattermost 5.12.0-2

Expected behavior

N/A

Observed behavior

{"level":"debug","ts":1561505102.811418,"caller":"app/app.go:136","msg":"not found handler triggered","path":"/","code":404,"ip":"my ipv6 (X-Forwarded-For)"}