SSO and ADFS. Server returned invalid response: unexpected HTTP status code

[Seekinsj]

I am getting a Server returned invalid response: unexpected HTTP status code.

I have followed the ADFS OIDC setting by Bitwarden. https://bitwarden.com/help/adfs-oidc-implementation/
And tried to adjust it according to the vaultwarden SSO Wiki.

The main difference I believe is that the callback is supposed to be https://your.domain/identity/connect/oidc-signin instead of https://your.domain.com/sso/oidc-signin.

Below is the logs I pulled from my docker container.

vaultwarden | [2025-09-19 15:31:34.750][request][INFO] GET /api/config
vaultwarden | [2025-09-19 15:31:34.767][response][INFO] (config) GET /api/config => 200 OK
vaultwarden | [2025-09-19 15:31:44.019][request][INFO] GET /api/config
vaultwarden | [2025-09-19 15:31:44.019][response][INFO] (config) GET /api/config => 200 OK
vaultwarden | [2025-09-19 15:31:44.031][request][INFO] GET /api/devices/knowndevice
vaultwarden | [2025-09-19 15:31:44.066][response][INFO] (get_known_device) GET /api/devices/knowndevice => 200 OK
vaultwarden | [2025-09-19 15:31:45.616][request][INFO] POST /api/organizations/domain/sso/verified
vaultwarden | [2025-09-19 15:31:45.637][response][INFO] (get_org_domain_sso_verified) POST /api/organizations/domain/sso/verified => 200 OK
vaultwarden | [2025-09-19 15:31:45.659][request][INFO] GET /identity/sso/prevalidate?domainHint=Vaultwarden
vaultwarden | [2025-09-19 15:31:45.671][response][INFO] (prevalidate) GET /identity/sso/prevalidate => 200 OK
vaultwarden | [2025-09-19 15:31:45.702][request][INFO] GET /identity/connect/authorize?client_id=web&redirect_uri=htt
vaultwarden | [2025-09-19 15:31:45.927][response][INFO] (authorize) GET /identity/connect/authorize?<data..> => 307 Temporary Redirect
vaultwarden | [2025-09-19 15:31:59.266][request][INFO] GET /identity/connect/oidc-signin?code="Ideletedthiskeyjustbecause"
vaultwarden | [2025-09-19 15:31:59.276][response][INFO] (oidcsignin) GET /identity/connect/oidc-signin?& => 307 Temporary Redirect
vaultwarden | [2025-09-19 15:31:59.878][request][INFO] POST /identity/connect/token
vaultwarden | [2025-09-19 15:32:02.451][vaultwarden::sso_client][ERROR] Request to user_info endpoint failed: Server returned invalid response: unexpected HTTP status code
vaultwarden | [2025-09-19 15:32:02.452][response][INFO] (login) POST /identity/connect/token => 400 Bad Request
vaultwarden | [2025-09-19 15:32:02.604][request][INFO] GET /api/devices/knowndevice
vaultwarden | [2025-09-19 15:32:02.606][response][INFO] (get_known_device) GET /api/devices/knowndevice => 200 OK

I have vaultwarden behind Nginx Proxy Manager. I am guessing that I am getting the error because I need to do something to NPM.
I have added the below to the custom Nginx Configuration advanced setting.
proxy_ssl_server_name on;
proxy_ssl_name $host;
proxy_ssl_session_reuse off;

I am wondering if anyone might have an idea if I am headed in the right direction, or might have a suggestion on fixing this issue.

Thank you

[Seekinsj]

I have now tried removing Ngnix Proxy Manager from the equation.

That has not fixed the situation.

I am still getting these errors

vw | [2025-09-19 22:44:27.542][vaultwarden::sso_client][ERROR] Request to user_info endpoint failed: Server returned invalid response: unexpected HTTP status code
vw | [2025-09-19 22:44:27.542][response][INFO] (login) POST /identity/connect/token => 400 Bad Request