Xcode shows warning after adding App Groups (Add the "App Groups" entitlement to your App ID)

I faced the same issue, and in my case my apple id did not have the permission to add the "App Group".

If your account's type is "Member", not "Agent", then you need your Agent/Admin who has the main development account to add the "App Group" for you.

For me, what worked was I had to changed the Bundle Identifier because I was working with a project template I had downloaded from the internet.

You can change that in:

Project Navigator -> Target -> <Your target> -> General tab

After that, I checked the App Groups and the warnings had gone

For me, what worked was having the phone attached. Once I attached it, Xcode was able to finish the process and the two red check mark problems were resolved.