Either a computer restart or a clean installation might help here.
How to fix your Studio installation / Licensing issues
There are also a few older topics with this error message that have a post marked as a solution:
https://forum.uipath.com/search?q=%22Activation%20failed%20with%20error%3A%200%22%20status%3Asolved%20order%3Alatest
ashokkarale
sharazkm32
sonaliaggarwal47
LamaX