u/Adventurous-Past4757

We're having on-premises Exchange servers and when I want to add mailbox to outlook for iOS (iPhone), it keeps redirecting me to the Authenticator App, Sign In to Microsoft account page. Even if I try to enter my email address there, it says that email address doesn't exist (we don't have m365). Did anyone face this issue?
Just want to add that it is the same if I try to manually add an account (with server, domain, and other details)

We have a hybrid environment, and we're having the following difficulties. When we reset a laptop, and once the user login there is 2 entities showed up in Entra. One entity is entra registered and that is automatically joined to Intune, and the other one is a hybrid join in pending mode, which is not on Intune.
The ideal scenario is to be hybrid joined and on Intune. What are we doing wrong? Please don't bother to comment about hybrid environment, because we couldn't go with full cloud for some reasons.
EDIT: It's no longer in pending status after entraconnect sync. But the problem is still the same, double entity.