OAtuh/OpenID configuration not working

Hello,

I have a web portal application called app installed on IIS

URL of the app : https://iamweb.xxx/app

This app is then proxied with BigIP F5 like this :

URL :    https://bigip.xxx/app

So that https://bigip.xxx/app  redirect to https://iamweb.xxx/app

I have set up every thing to use OAuth/OpenId to log to this webportal app according to this doc:

support.oneidentity.com/.../27

I  use a weel known external identity provider..

But when i go to : https://iamweb.xxx/app  (or https://bigip.xxx/app)  , it s supposed to redirect me to the identiy provider login page, but it s only loading the app..

Any hint how to debug ?

Kinf regards,