If you purchased the API via a group buy, you have to ensure that the same API isn't being simultaneously used by another person who shared the API with you, otherwise, if accessing the API too quickly, that may get your API key blocked on Moz. You can in fact create 5 or 10 APIs with Moz for free, which you can load those up into Scrapebox, and that should allow you to check the metric better through those accounts.