Ad manager and admob connection

I have added my new app to ad manager. All process was ok. And one day later, I received an email from Admob saying “We completed our app review. The following app has been approved and enabled for ad serving”.

I am confused. I do not know the relationship between admob and ad manager, beyond the fact that they are both owned by google. Can anyone explain this? Why this connection if both systems are independent?

AdMob and Ad Manager aren’t related except that they both use AdSense to send payouts. Unless you previously signed up for AdMob and listed your app there, I’m not sure why you received that email. Perhaps you could share the exact contents and sender of said email for additional context.

hi again,
I did not previously sign up for AdMob and did not register the app in AdMob…
The content of the email is the following: