Mail app on macOS does not fetch or send new mail.

Same issue. Able to replicate on two macs both trying to log into the same email account. I am able to login to my email in OWA on both machines no problem. This issue just started this morning.

I also tried adding the exchange account manually, but it said my password was incorrect (I know its not b/c I just used it to login to OWA). When I switch it back to automatically adding the exchange account does everything you expect it to until you open Apple Mail.

Also, the calendar sync seems to be working fine, only Apple Mail.

Same issue. Started this morning. Tried everything, even deleting certain system mail files in order to force it to reinstall. That didn't work either. Same as all users above. Works on everything else, just not MacOS on my MacBook M4.

Same thing here, I have 2 emails but only one of them is not working on my mac desktop. But it does work fine on my iphone.

Ok. So I have same problem as everyone else on this Thread today. My last successful email came in at 9:08pm on 2/4/2026. I see this thread started about 12 hours before my issues.

I've done a bunch of testing today and here's what I know.

I have 5 Godaddy emails for various things on my MacOS Big Sur 11.7. 2 of the 5 stopped working with the error…

Connections to host (null) on the default ports failed.

3 emails continue working on MacOS Mail. 2 Broken ones have the triangle.

Email provider is Godaddy which sends us all now to Microsoft Exchange Mail.

Connection doctor on Mac can't ever get to the server. Tried deleting one of the broken accounts from MacMail and re-adding. Same issue. Have tried everything, removing hidden keys, checked for viruses, rebooting, updated MacOS to latest version of Big Sur (11.7.11), tried to manipulate manual exchange settings nothing. Tried deleting one of the 3 working email accounts in MacMail and re-adding. This worked fine for a previously working email.

I can successfully access the 2 MacMail broken email accounts via Web Login to Exchange fine. iPhone access to the broken emails continues to work fine and never stopped working for the 2 broken accounts.

The 2 broken accounts are on the same domain. I've tried other emails on same domain in MacMail and they are fine.

Went home and got on my iMac with latest Sequoia 15.7.3 that is a relatively new build and has never had any email accounts on it. When adding these 2 Broken emails to this Mac they still don't work on a fresh machine with the latest version of MacOS. Emails that work on other machine work just fine in MacOS mail on the home machine when added.

Bottom line. I believe that I've eliminated enough variables to determine this is likely NOT a Mac issue. It is a Microsoft Exchange problem. There appears to be an issue somewhere deep in the Microsoft Exchange code somewhere that breaks some emails with some particular setting. The fact that 2 of my 5 are not working and others are posting it must be fairly widespread. -- but only with MacMail users.

MICROSOFT HELP INVESTIGATE AND SOLVE THIS PROBLEM!!!

Any idea from anyone on how to get Microsoft's attention on this?

Thank you.

Moderator note: PII removed

I have gone through the exact same issue all day with a client who has domains and Exchange email account through GoDaddy (he's in Colorado).  This began happening for him around 7:30 PM on February 3, 2026.

I ALSO have my domain and Exchange email accounts through GoDaddy and they are working just fine (I'm in Los Angeles).

I created fresh temp logins on both of his computers to test his Exchange accounts and my account. My account works fine, but his two accounts exhibit the same issue as on his normal computer logins.

I added his Exchange accounts to a test computer with fresh temp logins I have with both MacOS Systems replicating his setup, macOS Monterey (12.7.6) and macOS Sequoia (15.7.3), and even tried on another test computer with macOS Tahoe (26.2) ALL with NO success.  But again, adding MY Exchange email account was successful on all.

Both of his accounts DO work using Microsoft Outlook app for Mac on both of his two computers where they aren't working in the Apple Mail app.

His iPad and his Android phone are BOTH working with the same accounts in question.  It's ONLY the Apple Mail application on his two computers that will not work.

I also tried changing the password on one of his accounts to see if that would make a difference - NOTHING!

Calling GoDaddy was futile. They said it was an Apple issue, but I know if I call Apple, they will blame it on Microsoft or GoDaddy.

I would like to contact Microsoft for this issue, but can't find a number for the best department.

MICROSOFT, CAN YOU BE OF ANY ASSISTANCE WITH THIS ISSUE ?

I've got a couple leads that I'm tracking down. I had ChatGPT to a Pro level investigation and it possibly could be EWS is not set correctly for a particular domain or user. Apparently the flags associated with it have started be enforced for some recently. Still researching.

Dear users,

Could everyone please review the response below before I send it to the user?

Thank you very much for your understanding.

I have the same, very frustrating, issue. One out of my four Exchange accounts refuses to work on the Mail app on my Mac. The same account works just fine online and on other devices. The account in question has a warning sign next to it in the Mail app that shows the message "Connections to host (null) on the default ports failed." when clicked. In the Mail app Settings > Accounts (for the account in question) > Server Settings shows the Outgoing Mail Account as being Offline.

Here is some additional information in case it is useful:

Location: Ahmedabad, Gujarat, India

Mac: M2 MacBook Air

OS: macOS Sequoia 15.7.3

Mail app: Version 16.0 (3826.700.81.1.4)

As of overnight in Central Time Zone my issue has resolved

Resolved for me now

This has also been resolved for me in Central Time Zone.

Resolved in SE Texas

Almost fixed here in OH too. Old mail came fast but for some strange reason new mail is kind of an issue.

Hi,

I'm having that issue since today morning.

Account still work on my iPhone without issue.

@Emma1-N how to manage this ?

Thanks in advance.

I am also currently having this issue. It seems like not a coincidence that we're both commenting here this morning, I suspect it means there's an outage or a bug happening?

how to fix this?

Two of my users are also experiencing this issue. I’m currently investigating it and have already tried several troubleshooting steps, including removing and re-adding the account and resetting the outgoing mail server settings.

Unfortunately, no luck so far. Has anyone encountered this issue before or know how to resolve it?