Question: iMessage Authentication Fail
FaceTime and iMessage haven't been working on my laptop for a while and each time I try to sign in it says 'iMessage Authentication Fail' or 'An error occurred during activation. Try again'. It also doesn't work on my iPod and says 'Error occurred during FaceTime activation' (even if signing into iMessage). Any ideas?
MacBook Air, macOS High Sierra (10.13)