If you are using the Amazon Machine Tags plugin for WordPress then you are aware that Amazon recently changed their policy for the Amazon Product Advertising API and now will require that all requests are authenticated. Initially with the AMT (Amazon Machine Tags) plugin you wethe re only required to have the Amazon Access Key ID configured and not the Amazon Secret Access Key. Most people probably already had the Secret Access Key configured however if you did not have your “Secret Access Key” configured then after upgrading the AMT plugin will no longer work. If this is the case then your Amazon Machine Tags will display like the below in your WordPress posts instead of displaying the product properly.
Example AMT WordPress Post Tag: “[ amtap book:isbn=0596510489 ]”