Sequoia Update 15.3.2 iMessage NOT syncing across iPhone and Mac

I'm having the same problem. Have tried every solution. When I reboot my laptop imessage work fine for about 5 minutes. I'm able to send to iphone users using imessage (messages are blue) and then shortly after the messages default to SMS (green) and often don't send at all. Very very very frustrating and I've lost hours trying to figure this mess out. I feel stuck in a microsoft **** only it's apple.

There's a setting on the iPHONE, messaging app setting about halfway down, called "Text Message Forwarding". Make sure your MAC is set to "ON" for this setting. I just got new Mac, and it wasn't getting the SMS messages even though my older Mac and other devices were. I found this setting ON THE PHONE, and that's what is needed to fix (at least) my problem.

chuckfromrockford wrote:

Since updating to 15.3.2 last week(March 19), my Mac Mini iMessages no longer sends or receives any kind of SMS message or other reliably.

I've tried all the usual advice with deactivating/activating iCloud messages, shutting down each device, manually syncing with iCloud, turning the internet connection on/off, etc. Nothing gets iMessages on my Mac Mini to work.

The iMessaging app on my iPhone is working fine.

Very annoying, to say the least.

to jump start the syn between device that use the same AppleID/Account

the go to way is sign out and back in again

Sign in to or out of your Apple Account on Mac

ref: What is the difference between iMessage, RCS, and SMS/ ...

The current stable release of Sequoia including bug fixes, security updates is macOS 15.3.2

Keep your Mac up to date - Apple Support

Keep your Mac up to date - Apple Support

The current stable release of iOS including bug fixes, security updates is iOS 18.3.2

Update your iPhone or iPad - Apple Support

I had the same issue with syncing process between MacBook Pro (M1 Pro 2022 / MacOS 15.3.2) and iphone Pro 16 iOS 18.3.2 is broken. Happened between Sonoma and iOS 16 too.

I have to different sets of iMessages & SMS on MacBook & iPhone. I tried to remove all messages and switching sync in the cloud off and then back on but id does not help.

It seems like if iPhone & Mac are near each other and are on - the messages are is sync, but when I'm away and send/receive few messages on iPhone they stay on iPhone and does not sync to Mac and vice versa.

Manual workaround to that works, but you have to do it every few hours:

On your iPhone, go to Settings -> <your icon at the top> -> iCloud -> Show All -> Messages in iCloud -> Sync Now

On your Mac, go to System Settings -> <your icon at the top> -> iCloud -> Show More Apps -> Messages in iCloud -> Sync Now