Please make sure that you are signed into the Splice desktop client with an account that has a Serato Sample plan active before you open up your DAW to load Serato Sample. While you are on the Rent-to-Own plan, the client needs to verify the Serato Sample plugin once every few days.
This fix may also apply to users being prompted for a serial number. Please see below for screenshots.
If you've fully paid off your Serato Sample Rent-to-Own subscription and are being prompted for a serial number, your serial number will be shown here:
If issues persist, please contact firstname.lastname@example.org.