Caddy 2.11.1 breaks OpenCloud

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1

1. The problem I’m having:

Running opencloud baremetal. Caddy as simple reverse proxy in front. Worked until the upgrade to 2.11.1:

2. Error messages and/or full log output:

OC login screen shows:
Failed to connect to server
Unexpected HTTP response: 400. Please check your connection and try again.

Screen Shot 2026-02-25 at 23.11.37
Screen Shot 2026-02-25 at 23.11.37600×278 12.6 KB

Reverting back to v2.11.0-beta.2 fixes the problem and it works again.

3. Caddy version:

v2.11.1 h1:C7sQpsFOC5CH+31KqJc7EoOf8mXrOEkFyYd6GpIqm/s=

4. How I installed and ran Caddy:

Downloaded binary runs as service

a. System environment:

Debian GNU/Linux 11 (bullseye)

2

Ok - already found the culprit, problem is the Host Header change in 2.11.1:

Reverse proxy now automatically rewrites the Host header to the address of the upstream when the upstream is HTTPS

adding

header_up Host {host}

to the reverse_proxy declaration fixes it!

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3

Yeah, sorry if that broke you. The previous default was insecure in some common configurations.

It’s probably best to explicitly pass-thru the client-facing hostname to the backend if that is what is needed. Although, that sounds like it would almost always surely be wrong… right?

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