Signature validation failed to fulfill the request.

[lubefinder]

Constantly getting the following error on every signed request I try on production with my production pk/jwe and valid access token. The same code works on sandbox with my test user/test pk/jwe and sandbox generated token.

{
  "errors": [
    {
      "errorId": 215122,
      "domain": "ACCESS",
      "category": "REQUEST",
      "message": "Signature validation failed",
      "longMessage": "Signature validation failed to fulfill the request."
    }
  ]
}

I get the same results using the example-GET.php program in the eBay official PHP SDK. Any clues on why the same code works on sandbox, but not on production?