Make sure you have your phone number added to your Apple ID account online.(Don't want to do this - shouldn't have to) Delete all your previous conversations: Some people have reported that they had to delete all of their conversations before things would sync up.Disabling then re-enabling iMessage on each device that isn't being synced to.If you are still having trouble getting new iMessages to sync across the devices try: ( Still having trouble.) Note that only new iMessages will sync - history will not. (Image 1 below: under: Start New Conversations From - Should I select my Apple ID email address?) The most important part is that everything is consistent across all the devices. (My only option here is to select my Apple ID address) Select your phone number and any email address(es) that you would like synced.Select your iMessage/Apple ID account, and make sure "Enable this account" is checked.On each Mountain Lion Mac: (My note: I am on: OS X El Capitan Version 10.11.2) Select your phone number and email address(es) that you want to sync to that device.Make note of the Apple ID at the top of the page.If iMessage is on, "Send & Receive" will appear below it.Go to "Messages" and make sure iMessage is On.On each iOS device (iPhone, iPod Touch, iPad, iPad Mini):
"First, you need to make sure all your devices are on the same Apple ID." Here are the steps I followed in the 2nd link you provided: Messages – Fix Syncing Between Mac and IOS (2) Unfortunately I still cannot sync between my iPhone 5 and iMessage on my MacBook. Thank you for taking the time to respond to my inquiry. When I try to send another message in iMessage on my Mac, I still receive a Not Delivered notification and the SMS message bubble is green.
If you recently signed into "iPhone" you can ignore this notification." After clicking on OK in that message, then trying to activate Text Message Forwarding again, I still do not get notification of a code shown on my Mac. However, when I activate iMessage on my iPhone, I do get the following message on my Mac: " Your Apple ID and phone number are now being used for iMessage on a new iPhone. On my iPhone, when I navigate to Settings > Messages - turn off iMessage then turn it back on, once it activates and presents the "Text Message Forwarding" option, after tapping on the button activating it, I receive the "Text Message Forwarding" message where I can enter the code that will be shown on my Mac but the code never appears on my Mac. I repeated the steps suggested in each several times. I exactly followed the steps in the sequence suggested by both GregCAust and brenden dv at this thread Text Message Forwarding confirm code won't show up in Mac without success.
In System Preferences > iCloud - I am signed into iCloud My iCloud / Apple iMessage account says "(inactive)". Both are "greyed out" and not accessible when I click on them. When I open iMessage Preferences > Accounts - there are two accounts listed: my iCloud / Apple iMessage account and Bonjour. The selected contact, in the "To" field has their name in a red background and each time I try to send a message I receive a "Not Delivered" notification. On my Mac, when I open iMessage, each of the contacts have the word "Offline" below their names. I have followed the suggested "fixes" in various threads here as well as elsewhere.
IMessage used to sync between my MacBook Pro and iPhone but is no longer doing so.