Use the Licensing tab to refresh the current status before assuming a purchase or registration has failed.
For a pending purchase, wait for Google Play verification and reopen the plan list if it fails. If access is missing, confirm the purchasing Google account, refresh the status, and open Google Play management from the app. Prepaid plans stack; review the timeline before buying another plan.
Check the purchase email and license key carefully. A Demo key cannot activate the Plus app. For a temporary verification error, try again after confirming internet access. You can delete local registration data and re-register when moving to a new device or after correcting the entered data.
Never send a full license key in public. If a key is reported as invalid or disabled and you believe that is incorrect, use Support and include the error message, app version, and purchase source without exposing the key.