S3 bucket not accessible after wrong policy added by Admin

It sounds like you have added a Deny rule on a Bucket Policy, which is overriding your Admin permissions. (Yes, it is possible to block access even for Administrators!)

In such a situation: Log on as the "root" login (the one using an email address) Delete the Bucket Policy Fortunately, the account's "root" user always has full permissions. This is also why it should be used infrequently and access should be well-protected (eg using Multi-Factor Authentication).

You can also open a support case and they can assist you further on the same.