Error: missing Upgrade header - PBS behind traefik


Jan 3, 2022

I am trying to get PBS working behind traefik reverse proxy.
At the moment all my services are running behind traefik and i got no problems.
PVE works, pbs webinterface works and 10 other websites are working well.

But trying to make a backup from pve to pbs using the fqdn to get routed through traefik does not work.
I get this error Message:
INFO: Error: missing Upgrade header

I also found these threads but they did not resolve the problem:

I also read the bug report and startet a lxc container with apache2 to test the config from Max Carrara.
It does not work at all. I get the same error.

Summing up:
  • Backup Job from pve to pbs to local ip address with port 8007 --> works
  • Backup Job from pve to pbs as pbs.domain.xy with port 443 with traefik as reverse proxy --> not working, missing upgrade header
  • Backup Job from pve to pbs as pbs.domain.xy with port 443 with apache2 as reverse proxy -> not working, missing upgrade header
I already tried some different configuration but i got no working result.

Someone got an idea how to fix this issue?

I can use tools like curl etc. but I do not really know, where i have to start at pbs to investigate this.
Maybe someone can support me here?
Last edited:
if there already is a bug report, please post your findings there (with the necessary detail, like proxy config & version, exact client commands used for testing, etc.pp.)
I'm joining in with the same problem, but behind Caddy instead of traefik.

(headers) {
header -x-powered-by
header -server
header Content-Security-Policy "frame-ancestors 'self'; upgrade-insecure-requests;"
header X-LB-Server {system.hostname}
header X-LB-Requested-Host {host}
header X-LB-Server {system.hostname}
header X-Forwarded-Port {http.request.port}
header X-Forwarded-For {http.request.header.CF-Connecting-IP}
header X-Real-IP {http.request.header.CF-Connecting-IP}
encode zstd gzip
}, {
import cloudflare
import headers
reverse_proxy {
transport http {

I am on the latest build of PBS. I would greatly appreciate a solution that will work with my architecture using a cloudflare tunnel.


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