An error occurred (AccessDenied) when calling the PutObject operation

Your AWS credentials don’t have permission for this action.

Fix 1: Check your credentials

aws sts get-caller-identity

Make sure you’re using the right profile/account.

Fix 2: Check IAM policy

The user/role needs the right permissions. Example for S3:

{
  "Effect": "Allow",
  "Action": ["s3:PutObject", "s3:GetObject"],
  "Resource": "arn:aws:s3:::my-bucket/*"
}

Fix 3: Check bucket policy

S3 buckets can have their own policies that deny access:

aws s3api get-bucket-policy --bucket my-bucket

Fix 4: Check for explicit denies

An explicit Deny always wins over Allow. Check all policies attached to the user/role.