This morning, all of my Exchange accounts in Apple Mail on macOS began showing exclamation marks and stopped syncing. The accounts still work normally in Mail on iPhone, Outlook, and webmail. I've tried rebuilding the envelope index, removing and re-adding the accounts, and checking Connection Doctor, which reports that the connections are fine. Is anyone else seeing this, and is there a known fix or timeline for resolving it?
4 Answers
The official account-reconnection steps have not helped everyone. If the account works on other devices and clients, repeatedly removing and rebuilding it is unlikely to make a difference.
This appears to be a widespread issue affecting Apple Mail on Mac, rather than a problem with an individual account. Several people reported the same failure across multiple Macs and Exchange accounts while iOS Mail, Outlook, and webmail continued working normally.
Rebuilding the mailbox, deleting and recreating the account, and restarting the Mac don’t seem to resolve it. Some people suspected an Exchange Web Services change, but re-enabling EWS did not fix the problem, so the issue may require a server-side or Apple Mail compatibility fix.
The problem has been reported across offices and multiple computers, with users still able to send in some cases but unable to receive new messages. Until Apple Mail starts working again, Outlook or webmail appears to be the practical workaround.
That matches what I’m seeing too—Apple Mail is the only client that stopped receiving messages, even though Connection Doctor reports everything as connected.