Need help with connecting as OAuth provider to Authentik

i_like_beef

Hi all,
I’m trying to setup my mailcow instance (running on a VPS) as an OAuth provider for my Authentik instance (running behind a reverse proxy in my homelab). I’m using NGINX Proxy Manager as reverse proxy.
I was following the the Authentik guide on setting this up (https://goauthentik.io/integrations/sources/mailcow/), which is also linked here in the forum…
Unfortunately I can’t get this to work. When I choose to login via Mailcow, I am redirected to the following address:
(xxxxx means I have anonymized some parts)
https://mail.xxxxx.xxx/oauth/authorize?client_id=XXXXXXXXXXXX&redirect_uri=https%3A%2F%2Fauth.xxxxx.xxx%2Fsource%2Foauth%2Fcallback%2Fmailcow%2F&response_type=code&state=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX&scope=profile

Basically that doesn’t seem wrong to me, but in the browser I just get an error code as an answer:
{“error”:“redirect_uri_mismatch”,“error_description”:“The redirect URI provided is missing or does not match”,“error_uri”:“http:\/\/tools.ietf.org\/html\/rfc6749#section-3.1.2”}

Can anybody provide me some help or point me in the right direction?

Thanks in advance and BR!

tig987

Hi,
I ran into the same issue.
The guide at https://goauthentik.io/integrations/sources/mailcow/
has an error in their example for the Redirect URI.
The Redirect URI entered in Mailcow needs to have a trailing slash /
it must be like this
“https://authentik.company/source/oauth/callback/mailcow/”

i_like_beef

Hi tig987 , thanks for pointing that out - you’re a genius! 🙃
This really solved my issue after I have already given up on that feature! There’s no way, I had seen that missing trailing slash. Now it works like breeze 😀