Facebook API - Login to Xojo web-app

Hi to all,
I am looking a way to use facebook log-in credentials to my Xojo webapp using Mathews Combatti Facebook API v2.5. I get error and i suspect that despite of following the instructions in setting a developers facebook account I have type wronly the Valid OAuth Redirect URIs.
Is anybody who has using Mathew’s API or have use Facebook in his/her webapp to give me a hand. I have really stuck in it.
PS: I can access Facebook API correctly from a desktop app as it does not need the Valid OAuth Redirect URIs to be filled in with…
Any help appreciated in advance.

Are you trying to use it from a specific session in the web app or something else ?

Are you deploying this application to a server or is this just local testing?

I maybe found the solution… locally it works but not on server but think is a matter of settings FB developer… the think is that setting the privacy statement i should provide a webpage but i dont know as xojoserver host my webapp. I have also a problem with setting correctly the Valid OAuth Redirect URI.