If you are using Video AI version 3.0.X and you see watermarks on your output file despite owning an active license, please update to v3.0.12
If that does not work, please close Video AI and delete the auth.tpz file from your system.
This can be found under the following locations;
/Applications/Topaz Video AI.app/Contents/Resources/models/auth.tpz
C:\ProgramData\Topaz Labs LLC\Topaz Video AI\models/auth.tpz