似乎是由于您得到的错误

It seems from the error you are getting

  Access to Identity 'us-east-1:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx' is forbidden

您在第一部分中获得的凭据无法访问您进行同步调用的身份，因此您的身份可能已更改.

that the credentials that you obtained in the first part cannot access the identity you have made the synchronize call with so your identity probably changed.