Amazon Products API Help: The Access Key ID or security token included in the request is invalid.

Hi, I have been trying to get started with the amazon products API, and I am currently an affiliate, which means I should already have access.

Upon setting up a new project with some of Amazon's sample product search code, and inputting my access key/security token, it gives me the error "The Access Key ID or security token included in the request is invalid."

I've looked at the documentation here https://webservices.amazon.com/paapi5/documentation/quick-start.html.

I tried running a search on https://webservices.amazon.com/paapi5/scratchpad/index.html with the store ID and key/token and it said "Error! InvalidSignature The request has not been correctly signed. If you are using an AWS SDK, requests are signed for you automatically; otherwise, go to https://webservices.amazon.com/paapi5/documentation/sending-request.html#signing."

I have emailed about this several times, being told to wait 72 hours and I have done that. I generated new keys, and got the same result. Finally I was told to post here for help, so I hope someone here can assist me. Judging by the tags offered on this post, this seems like it's not the right place for this question... but I'm sure someone here may still know better.

If you need more information let me know. Thank you!