Amazon MWS API credentials are required for Amazon Analyzer to access data from the Amazon API. These credentials are found in Amazon Seller Central and require a professional seller account. Analyzer.Tools pulls all data for its FBA fee calculator, including FBA shipping costs, and all other fees directly from Amazon using these credentials.
Invalid API credentials errors can have a limited number of reasons, which are listed below:
Therefore, this error can only have a limited number of reasons, which I will list below:
1) Credentials are incorrectly entered into program, please be
sure to follow our instructions for this (step 3 of this article), do not use credentials from an old program & make sure to use the correct region developer ID (most common reason),
2) Credentials are invalid if you a) do not have an Amazon professional seller account, or b) your professional seller account is not in good standing or c) your professional seller account is new and pending verification,
3) You selected the wrong region link to generate your credentials. Be sure you selected North America (includes Canada, US, and Mexico) or Europe (includes Spain, UK, France, Germany, and Italy) correctly under step 3 of this link. If unsure, generate the keys again by clicking the correct region link and try again,
4) Your computer system time is not current. The API requires a
current (live) system date and time. See if your system date/time is set to “automatic” in Windows,
5) Internet connection or Amazon API downtime issue (very rare).
Once you enter your credentials into the program, click “test” and look for a “Success” message. Be sure to click “Save” after successfully testing.