You received the license key from ShortPoint and tried to activate the license key on ShortPoint License manager in SharePoint Central Administration. Then you got this error:
The SharePoint user you are using to activate ShortPoint License is not a Local admin of the SharePoint Server machine or he is not a SharePoint admin.
You need to be the Local admin of the SharePoint Server machine and also SharePoint admin to activate your ShortPoint. Please make sure the account you are using has all these requirements.