Here are some possible reasons.
1)Check if you have logged in UniConverter software.
After purchase, you can try to re-login or restart the software to refresh your account status.
2)Check the expiration date of your subscription plan.
3)Check if you have purchased the correct platform and correct product.
4)Please kindly note that the perpetual license authorizes you lifetime access to only the major version that has been purchased and you can get minor updates for free within this major version. But it does not include new major upgrades. For example, you can get an upgrade from Uniconverter 13.0 to 13.2 for free but an upgrade from Uniconverter 13.0 to 14.0 require a payment.
If you bought an old perpetual license for Uniconverter 12/13 before 04/30/2022, that license won't activate the Uniconverter 14.0 without your paying for the upgrade.
UniConverter 14 is a brand new product with more features and a better experience. Now is a good time to get the new product with special offers exclusive to our existing users. Actually, it does not conflict with the older version you have, and you still have access to the previous version whether or not you upgrade.
We highly welcome you to visit our upgrade page for more details: