How to upgrade xdcscan.com api to pro

how to upgrade xdcscan.com api to pro
when i use xdcscan.com to call interface
https://api.xdcscan.com/api?module=account&action=addresstokenbalance&address=0xFd92F4e91d54B9EF91cc3f97C011a6aF0C2a7eDa&page=1&offset=2&apikey=your key
,return this to me
{“status”:“0”,“message”:“NOTOK”,“result”:“Sorry, it looks like you are trying to access an API Pro endpoint. Contact us to upgrade to API Pro.”}