I have the same issue after upgrading a MacBook Pro 2019 to Big Sur and replacing the battery of a flic 1 button which was not recognised after replacing the battery. I removed and re-installed the flic.io app and since then I cannot re-install any of my three flic 1 buttons. The error message is the same. I opened a ticket for this issue.
Posts made by DDoEthan
RE: Issues connecting on OSX Big Sur (11.1) with flic 2