Assign Idp to certain application

Hi everyone,

I have multiple applications in my Okta Org, and I want to create an Idp for a certain application, where users logging in using that Idp will automatically be assigned to the application. Is that possible?

I am getting failure: user_not_assigned when trying to sign in with an Idp with the application credentials

Assign the app to the Everyone group or create a group rule which is assigned to app: