Error resetting last modified date

Alexander72 

What I am trying to say is if you are using Delegated Permissions (as mentioned in below screen shot), even if you provide higher permission in App Registration, only operation which current user have permissions (user which you have used in interactive login) are allowed.

E.g. In your App Registration, you have given AllSites.FullControl rights and let say we have two user i.e. User A and User B where User A does have only read rights in one site collection and User B does have contribute rights in same site collection.

Now if you login with User A in your CSOM console with interactive user, and you are trying to update anything in the site, Code will give unauthorized access (even if in your app you have given AllSites.FullControl permission) because current user don't enough rights in site collection.

I hope that now it will be more clear.

Hope it will helpful to you and if so then Please mark my response as Best Response & Like to help others in this community