Hi Dhiman..
Apparently there is some issue with your software. I think the installation of the license is not complete, if all other aspects like microprocessor bit size are compatible with your Optisystem software configuration.
I think you can first try uninstalling all the installation files of Optisystem from your pc. Both of the evaluation version and the licensed version. Then try re-installing. There is a chance some file of the evaluation version is conflicting with the licensed one. If that doesn’t work, we can figure out some other solution.
Regards
Naazira.