iMessage stopped working.. Contacts are shown as red now

This problem has been seen on mid-2012 MacBook Pros on Mavericks and on late-2014 Retina MacBook Pros on Yosemite.

One day while using iMessage on the Mac, all the contacts turned red and messages failed to send, immediately returning a "not delivered" error. It also reported when trying to resend the messages that the contacts were no longer associated with an iMessage account.

Things that didn't fix this behavior:

• Deleting the com.apple.ids.madrid

• Removing the Apple ID information from my phone, turning off iMessage on both of the devices, and placing my iPhone in airplane mode for several minutes before turning it on logging in again.

Could someone help me figure out how to solve this?

Solution 1:

One way you will get the red contacts is if the iMessages account is not enabled.

Go to iMessages's preferences. And make sure the enabled check box is ticked.

You Will also get the red contacts if you are not signed in. If that is the case you will need to sign in to see the enable check box.

Solution 2:

What I did that seems to have worked:

iOS Device > Settings > Messages > Text Message Forwarding

Turned off the selection for my iMac & then turned it back on. Entered the code that showed up on my computer & all worked again.

Solution 3:

Go to System Preferences and iCloud, then click on Account Details to verify your connectivity to iCloud.

If you've got:

Account Details could not be opened because of an error connecting to iCloud.

then try to Sign Out and Sign In again. One of the reason could be that Apple recently tries to force and upgrade security for users to use Two-factor authentication.

To check the iCloud errors, run the following command in Terminal:

log stream | grep -i iCloud | grep -C5 -i error

If the problem is somewhere else, try running the following log command in Terminal to debug the problem:

log stream --predicate 'processImagePath contains "Messages"'

or:

log stream | grep -C5 -w Messages

or check in Console app, then re-send the message and check for any hints or errors.