The installer cancels with «ZeroTier One.pkg can’t be installed because its digital signature is invalid»
I had same issue. I think you need to install an older version of ZeroTier:
Thanks, got it to work with 1.4.6 – there seems to be an issue with code signing in Big Sur:
Was experiencing the exact same issue. Went directly to 1.4.6 had it installed in less than 5 minutes. Thanks!