Key gives HTTP Status: 404 error

I input my 2nd license key for my new Mac and after installing NLP I put the key in but it never deactivated the “trial period” and now that the free conversions are done, I cant input my key without getting an “HTTP Status: 404” error. I tried resetting the preferences as stated in previous posts but still get the same error. I emailed customer service to potentially get my key reset but got no response. Thanks a ton in advance.