SMS stopped working in Messages on my iMac Pro

Hi,

It should be in Settings > Messages and then the Text Forwarding option.

It may pay to turn this Off, exit the settings then come back and reset.

Hopefully you will see a new Code Number appear on the first device you list to recreate the Link.

Also check your Mac and iPhone are in fact on the same LAN.

If, for instance, you run a WiFi network linked through a different router to the Ethernet side then they may sit in different Subnets then the Link will not work.

8:54 pm Wednesday; September 26, 2018

Hi,

The same Network refers to your Home or work LAN not the Carrier the iPhone uses.

Basically the iPhone is "Sharing" it's Carrier connection over the LAN to your Mac.

The Apple ID on the iPhone in Messages for the older Display on All Devices "Sync" (Pre OS 10.13.5 and iOS 12.4)

The Mac then gets the SMS messages via this link and uses the iPhone to Send them to the carrier and beyond.

The iCloud Sync of iMessages does not apply to the SMS items.

In Mojave I have not seen the Sync Now option appear anything that dark to sync again straight away.

I have a MacBook Pro running Mojave and an 27" iMac running High Sierra and both display they can "Sync Now". but in doing so does not sure an SMS thread on my iMac that is on my Macbook Pro as well as the iPhone.

Part of this issue for me is that as I Migrated an older Mac User Account to the new 27" it created the same Computer name so the iPhone had the Sync for SMS going to the wrong iMac.

Of course it will not play catch up.

9:38 pm Wednesday; September 26, 2018

In a somewhat similar situation. I can send SMS with my

phone number on my iMac but I don't receive any messages

for my phone number.

Also, I thought there was a "forwarding" switch on my iPhone 8

in Messages but it doesn't seem to be there any more unless I

am looking in the wrong place (iOS 12).

Closing Setttings on the iPhone and reopening brought back

the Forwarding switch (?). Turned it on and tested with a sight

with 2-factor ID and I got the authorization text on the iMac now.

Being on the same network has nothing to do with this particular

function (iPhone AT&T LTE/iMac on Comcast) and never did.

However part one of puzzle has been solved but part 2 in terms of

iCloud sync hasn't, even if the iPhone is on the same WiFi and subnet.

Again, being on the same network should not be a requirement as that

is the whole point of having things in iCloud is that they be accessible

from every where.

But, since it seems receiving texts on both devices is working, the syncing issue

is somewhat minor, for me at least, albeit annoying. What is odd is that the

"Sync Now" button is grayed out and I can only disable Messages in iCloud

on the iMac if I disable all.??