Upgraded iMac to 10.14.3 this morning. All went well but iMessage has not repopulated from my iPhone 6 (12.1.4). I can start & send new messages, but the conversations on my phone haven’t transferred to the iMac. I tried signing out of my iCloud account on both iPhone & iMac & signing in again. I also restarted the iMac. What am I missing?