Please be aware that there has been a recent change of implementation regarding Amazon's Product Advertising API limit.
According to Amazon Product Advertising API document, the allowed initial usage limit per day is 8640 requests and the limit for each account will be based on the revenue performance of your Product API during the last 30 days. They also mentioned that if your account hasn't generated any referring sales using Product Advertising API in the last 30 days, your account will lose access to Product Advertising API.
Our Amazon Import feature sends requests using Amazon Product API and once you've reached the limit, you will receive this error notice.
AWS Access Key ID:… You are submitting requests too quickly. Please retry your requests at a slower rate.
We suggest using the Amazon feature in moderation and enabling the Search Result Caching (ThirstyAffiliates > Settings > Amazon Import) to reduce the number of requests used from your Product API limit.
In case you lose access to Amazon Product API, you'll regain access once your account begins to drive referring sales again.
Read the full documentation here: https://docs.aws.amazon.com/AWSECommerceService/latest/DG/TroubleshootingApplications.html#efficiency-guidelines