Amazon Product Advertising API Error UnauthorizedOperation

I was able to configure everything with access and secret keys, however when trying to search for any ASIN or keyword I get the following message: “Amazon Product Advertising API Error
UnauthorizedOperation
Your AccessKeyId is not authorized to perform this operation. Please check IAM policies for the Access Key.”

When I go to ad authorizations to this user on Amazon, there are 231 possible authorizations that can be attached to any users. PLEASE HELP!!!!