iMessenger does not work on MacBook Pro

Just to clarify, do you mean Messages, the Apple pre-installed messaging program? "Messenger" is a Facebook/Meta program.

When it is not sending or receiving messages, are you getting any error messages? Have you checked your internet connection?

AppleBubbles wrote:

I just tried signing out and signing back in again, and that has kicked the program back into operation.

If it should happen again do the same with the FaceTime app. Sign out / sign in again, just like you did with the Messages app.

I know the two apps are not related, but when I experienced that problem I found that it also fixed Messages. The likely reasons follow below:

Yes, I have looked in the Keychain access for "Messenger," "iMessenger," and "Apple Messenger" and I cannot find anything under any of these names.

One reason is that there are no Apple apps by those names. You won't find any for Messages anyway (but you will find encryption keys for Apple's iMessage service). Your Apple ID / iCloud credentials are stored in a number of different encrypted Apple / iCloud entries. That's the reason signing out / in again tends to fix those kinds of problems. No need to use Keychain Access since that action updates them.

Here is what I would do. On your phone, sign out if iMessages and Facetime. Sign out of both on your computer. Restart both devices. Log back in on your iPhone. When everything is completely active on your iPhone, reactivate on your Mac.

Check to make sure that you have iCloud Messaging properly enabled:

Set up iCloud for Messages on all your devices - Apple Support

If you also want to receive SMS/RCS messages on your Mac, you'll need to set up text message forwardin. On your iPhone, go to Settings>Messages>Text Message Forwarding and enable it for your Mac.

I know IdrisSeabright addressed this already, but there is no iMessenger app. Your replies will continue to confuse us if you persist in referring to something that does not exist.

Are you posting from a location in the US? For all I know perhaps Apple calls their Messages app some other name elsewhere, but that would be news to me.

When it is not sending or receiving messages, are you getting any error messages?

The specific error message would be helpful.

Are these blue bubbles? Or green?