401 Unauthorized; Unrecognized Client

Hi,

According to the PA-API documentation, it seems to occur when an invalid API key is given.

UnrecognizedClientExceptionError Code:?UnrecognizedClientHTTP Status Code:?401 Unauthorized
If any client is not authorized to request Product Advertising API, this error arises.
The Access Key or security token included in the request is invalid.

Error Messages · Product Advertising API 5.0 (amazon.com)

So please try testing your keys on ScratchPad (Product Advertising API 5.0 Scratchpad (amazon.com)).

I’ve seen users who get PA-API errors when the keys are too new like in 24 hours. You might want to wait for a day or so to see if it makes a difference.