At some point all my Macs stopped being able to receive iMessages. They could just send. I tried signing out, nothing. I tried signing out and restarting, nothing. They continued to work on iOS devices, just not the Mac. Then I removed the email addresses from iMessage and that.....sorta fixed it? Now I get the messages but I get them hours later. Console shows "MessageProtection failed to decrypt with ngm identities - fail to unseal message {error: Error Domain=com.apple.messageprotection Code=5 "(null)", encryptingIdentity: <private>, signingIdentity: <private>}" but the problem is that Apple logging is the worst in the entire world. Seriously. This is from less than 60 seconds of MacOS logging in Console. What is the point of such a bad logging system? How am I supposed to figure out anything if you push 10,000 logs a minute of just errors?