[macOS 15.4.1, Mail.app 16.0]
I take advantage of Mail.app to entry 4 MS 365 accounts. One stopped with the ability to ship/obtain just lately (quickly after I up to date from 15.4 to fifteen.4.1?). Restarting Mail or the MacBook Professional would not assist. I nonetheless have full performance with the opposite 3. Close to the upper-right nook of the primary Mail.app window is the textual content “Account Error” with a triangle warning image. If I click on that textual content, I get a dialog with the message
On-line Standing
Connections to host (null) on the default ports failed.
I additionally tried going to System Settings -> Web Accounts -> drawback account after which toggling the Mail setting off, then again on. Nonetheless no luck. I can learn/ship email with this MS 365 account on my iPhone with no points.
I notice I can absolutely blow this account away after which re-sync every thing, however that is the account with 3GB of mail, and it might be a trouble to try this, so I am hoping to search out one other choice to this drawback. Thanks for any pointers!
EDIT:
Here’s a ping to Microsoft 365 SMTP:
>ping -c1 smtp.office365.com PING yyz-efz.ms-acdc.workplace.com (40.99.227.114): 56 information bytes 64 bytes from 40.99.227.114: icmp_seq=0 ttl=236 time=28.277 ms --- yyz-efz.ms-acdc.workplace.com ping statistics --- 1 packets transmitted, 1 packets obtained, 0.0% packet loss round-trip min/avg/max/stddev = 28.277/28.277/28.277/nan ms 
