What is the likely cause of this access denial?
The ACL in the bucket needs to be updated
The IAM policy does not allow the user to access the bucket
It takes a few minutes for a bucket policy to take effect
The allow permission is being overridden by the deny
Explanations:
ACLs (Access Control Lists) are not typically the cause of access issues if the bucket policy is explicitly set. The bucket policy overrides the ACLs in most cases.
If the IAM policy allowed access, it would not be the cause of the denial, especially when the bucket policy explicitly overrides permissions.
The changes to a bucket policy take effect immediately, so there would not be a delay causing the access denial.
In AWS, a deny statement always overrides an allow statement. The initial bucket policy likely had a deny all users statement, which is still taking precedence over the newly added allow statement.
I think the answer is:
The allow permission is being overridden by the deny