Hey there! Try removing the battery from your Rift S controllers for a minimum of 2-3 minutes to reset the wireless link. While they're out, check the compartments and terminals for any dust, debris or damage. Reinsert the batteries and try re-pairing. If the issue persists, click here to submit a ticket so we can look into it further. Thanks!
I ran into this problem in the early days, I had to uninstall their software and reinstall to get mine going