client behind proxy is failing to access Duende ID server

[vvsharath123]

Hi Team,

We are in the process of developing ID server 7 for our website and now stuck in test environment setup. but connectivity
from admin app client to ID server via proxy is failing with below errors

ERR 2025-03-07 12:16:44,553 - [ ] 800028e3-0000-e400-b63f-84710c7967bb :- IDX20803: Unable to obtain configuration from: 'https://Adminappproxy.com:8504/.well-known/openid-configuration'. Will retry at '07/03/2025 12:21:11 +00:00'. Exception: 'System.IO.IOException: IDX20804: Unable to retrieve document from: '[PII of type 'System.String' is hidden. For more details, see https://aka.ms/IdentityModel/PII.]'.
---> System.Net.Http.HttpRequestException: No such host is known. (https://DuendeIDserver.com:443)
---> System.Net.Sockets.SocketException (11001): No such host is known.

Actual URL of our id server is https://DuendeIDserver.com

Our Admin app client is sitting behind Apache proxy.

Actual Adminapp URI :https://Adminapp.com
Proxy Adminapp URI :https://Adminappproxy.com

Apache proxy uses ProxyPass

From our application prespective we have followed as suggested in https://docs.duendesoftware.com/identityserver/v7/deployment/proxies/
to configure the headers

Any suggestion will be of great help

[RolandGuijt]

It seems the discovery endpoint (.well-known/openid-configuration) can't be reached. Can you please try to access it directly with a browser and see if that works?

[vvsharath123]

Able to access discovery endpoint directly externally. We have one more client which is external facing .. redirection to id server is successful for this client

[RolandGuijt]

It looks like there is a misconfiguration somewhere. The error message states that the discovery document is expected on https://adminappproxy.com/ but that is the URL of the client.
Does this work in a non-proxy environment?
Please post the client configuration on the IdentityServer side and the code that configures authentication on the client so we can investigate further.