iMessage not working on Big Sur

Exactly the same for me, I called to apple support and they fix it in a couple minutes.

can you share what they did to solve it please.

Do you remember what they did to fix it?

I was told to restart my Mac and it worked!

This worked for me. I had the exact same problem when upgraded to Big Sur. Do a full restart/or shut down, and then launch iMessage again. Solved the problem on my end.

They didn’t told me, I have read in another forum that the apple ID were blocked (even working on iPad and iPhone).

I am having the same problem, after I updated I was not able to sign in at all, I sign in, and about a few moments later it prompts me to sign in again. I re-installed macOS Big Sur, and it did not resolve my issue. Even restarting the Mac, and not using it for a few days didn't fix my issue. I thought it would be fixed in a patch, but there hasn't been a patch since Big Sur came out. I would love to fix this.

can you tell me what they did to resolve this for you @Mardi

They didn’t told me, I have read in another forum that the apple ID were blocked (even working on iPad and iPhone).

Try to contact to apple support. They solve the problem (I don’t know how but they did it)

I had this issue for a week. Only when I used Safari did I realise what the issue was! I could not connect to any website. All Apple products did not work for me, Facetime, iCloud, Messages, even the app store was sometime intermittent. It also prevented me from installing Sophos End Point correctly, as it was blocking the autoupdate that installs the extension.

Somehow the settings in Safari/ as part of the Big Suck update toggled the network Proxies settings 'Auto Proxy Discovery'.

Just go to the wifi icon, click Network Preferences, unlock the padlock, enter your Mac OS user account password, click Advanced, select the Proxies Tab and then untick Auto Proxy Discovery.

Your welcome.

You mean "You're Welcome"? Yeah, no that didn't help. Big Suck is funny tho.. my Auto Proxy Discovery was already unticked.

But, still iMessage not working. I guess the joke is on us.. brand new computer or brand new OS and things don't work. Oh well, waiting on a fix or update.

So, imsg now works on my macbookpro... What I did...

1) Go to Messges app - Preferences - uncheck imessage on cloud

2) Sign out

3) Sign back in with your Apple ID password

4) Enable the settings again

Hope it starts working for you guys as well. It was so annoying when it didnt sync in real time...

Best wishes

-Farah

So when I tried to boot messages this morning in Big Sur, wouldn't open, got a kernel panic, but the notifications for them are showing.

Tried these steps to no avail:

1. boot to safe mode
2. reset nvram
3. moved to trash the .plist file in Library
4. reset SMC ( even thought I didn't expect this to help as it is used for power issues)
5. booted to recovery, ran Disk Utility (first aid) on all containers
6. reinstalled macOS from Recovery

Issue still persists, I understand that there are bugs, so hoping that Apple sends out an update to fix these bugs.

I had the same issue and talked with customer support.

HERE IS WHAT HAPPENED.

There is a chance your Apple ID was reported by someone as SPAM. So your further signing in was blocked on the server side. You have to talk to them to remove the blocking.