Activation Token- no associated order was found

I get the following error when trying to activate an exe file:

“Please verify your activation token because no associated order was found. JSON ERROR: Syntax error”

The JSON file is correct- product ID, privatekey, and masterkey. I have made multiple test orders of the product, yet I still get the above error.

If I try manual activation- the error is: “the key is not valid. cannot continue.”

“JSON ERROR: Syntax error”. This error is not from the workbooks.json file but from the WooCommerce REST API. Something on your server is corrupting the data returned by the API, so it’s not pure JSON data, as expected.