Ensure you are activating a version of TSplus that matches your key. A v15 key will not work on v17 software without an active Support & Updates subscription.
To obtain a TSPlus activation key, follow these steps: tsplus activation key link
If you have lost your original purchase email, you do not need to buy a new license. You can manage your keys through the TSplus Customer Portal. Ensure you are activating a version of TSplus
If you’re upgrading from an older version, the installer will detect the previous installation and ask if you want to keep existing settings—choose Yes . tsplus activation key link