Unexplained 404 Error after setting up Voidauth

[mpldr]

I got Voidauth setup, but for some reason get a 404 on an API call which makes me unable to login:

2026-04-13T16:09:35.809485890Z {"level":"info","message":"Starting VoidAuth Server","timestamp":1776096575809}
2026-04-13T16:09:35.951184105Z {"level":"debug","message":"Session Domain: '0x6d70.de'","timestamp":1776096575950}
2026-04-13T16:09:36.156451794Z {"level":"info","message":"Connected to postgres database.","timestamp":1776096576155}
2026-04-13T16:09:36.574244474Z {"level":"debug","message":"Attempting SMTP email connection.","timestamp":1776096576572}
2026-04-13T16:09:37.191496160Z {"level":"info","message":"Listening on port: 3000","timestamp":1776096577191}
2026-04-13T16:09:38.206586361Z {"level":"info","message":"SMTP email connection verified.","timestamp":1776096578206}
2026-04-13T16:20:20.139483168Z {"level":"debug","message":"API Response Sent","details":{"request":{"ip":"80.249.116.144","method":"GET","path":"/api/user/me"},"response":{"statusCode":401}},"timestamp":1776097220134}
2026-04-13T16:20:20.204802470Z {"level":"debug","message":"API Response Sent","details":{"request":{"ip":"80.249.116.144","method":"GET","path":"/api/public/config"},"response":{"statusCode":200}},"timestamp":1776097220202}
2026-04-13T16:20:20.234679722Z {"level":"debug","message":"API Response Sent","details":{"request":{"ip":"80.249.116.144","method":"GET","path":"/api/interaction/exists"},"response":{"statusCode":404}},"timestamp":1776097220232}

This is what the login form looks like:

The frontend seems to struggle with the response on /api/interaction/exists being the non-JSON: "Not Found". Is this a known issue that I have just missed? How do I manage to log in?

Edit: This is reproducible. Even after tearing down the environment and recreating it from scratch, this still happens.

[notquitenothing]

The 404 response being un-processable by the frontend framework is expected, if annoying. The regular initialization flow for a 'fresh' login page is to check for an existing interaction session (/exists), and if not found create one (auth endpoint api), and then check again (/exists again). Can you double check and see if these steps are happening in your logs?

[mpldr]

The second is also a 404, so there seems to be something weird going on: https://gist.github.com/mpldr/91d422d42e3ca0cc01403ae71814cf1e

[notquitenothing]

If the second one is also 404, that means that the session cookie could not be set. Could be APP_URL doesn't match what is in the browser URL bar, session domain of cookie isn't scoped right to set a base domain cookie, SESSION_DOMAIN environment variable is set but is not something the browser will accept, or cookie settings of browser. If you look at the request in the browser network tab after the first 404 (it should be something like /oidc/auth?...) it should be setting a x-voidauth-interaction cookie on a domain that matches the base domain of your APP_URL.