This signifies one of a number of issues:
a) your plugin has not been connected to your InAcademia Service subscription, or
b) your plugin has been configured to use the incorrect Redirect URI.
In both cases, you must visit Your Account and make sure that the values printed in your subscription details match exactly the value that was provided in InAcademia Plugin settings UI. It can take up to 15 minutes for the registration to complete in our backend systems. If you have checked the above, and waited at least 15 minutes, please raise a support request.
c) your subscription has lapsed (payment failed, card expired, or you cancelled your subscription).
In this scenario, if you’d like to continue using the extension, please renew your subscription; alternatively deactivate the plugin which will remove the Button and/or Notice from your shopping cart.