I purchased, installed, and successfully activated Scrivener 3 for Windows in May of 2021 and have launched it several times since then. However, twice now the program has evidently lost track of my activation and displayed the “Scrivener does not have a valid activation… Scrivener will now revert to trial mode” message when launched. Re-activating has worked (so far). It would be nice if it didn’t do this. (Windows 10 Pro, version 20H2. )
Contact L&L support directly (from the Contact Us page on their main website) so they can work with you to determine if there is an issue with your account and the licensing service. They cannot discuss licensing issues on the forum due to privacy issues.