Messages in the iCloud currently disabled .Repair Account

I have the same exact problem. I have a Mac running High Sierra 10.13.4 Beta (17E182a) and iPhone 11.3 (15E5211a) and I have the same message "Messages in iCloud is currently disabled, Repair Account".

Is this an iOS or MacOS bug?

Same here. I sent feedback. Just updated IOS which was pushed this morning 3/17. Didn't fix. I have iPad & iPhone linked and the functionality seems fine. In other words it appears to be a cosmetic bug. If I delete a text on my iPhone it's deleted from the other devices. I can send and recieve SMS texts from my Mac. I've logged in and out of iCloud on all devices, nothing's removed the error message. I presume it's a known bug by now-- annoying, but seemingly inconsequential. Let's hope it goes away with public beta.

I have several macs all upgraded with no problems to Messages. Then I setup a new test iMac and all icloud services work fine except Messages where the 'Repair Account' info is displayed. I've not yet found a way to get it to display historical messages, despite the many restarts, turning icloud on and off etc. It does display messages sent since the iMac started but nothing historical.

Did this ever get fixed? Just NOW happened on my iMac and the only thing that changed was I turned off two factor authentication so I could log into my old Apple TV with my iCloud address. I think I'll turn two factor authentication back on and see what happens.