DeNoise 3.1.1. does not open

Hi, I tested the trial version of DeNoise 3.1.1 - which worked - and then downloaded the paid version on Mac OS High Sierra 10.13.6. Now I can no longer open the tool. It shows the icon in the dock bar and pretends to be open, however I can’t bring it to the screen. No error message appears neither.
I already made a restart of the PC and an uninstall and new installation of DeNoise.
Any recommendation on what to do?
Thank you!