Problems with Apple Mail, Office 365/Microsoft hosted mailboxes and older Mac OS?

If you’re running an older version of Mac OS (such as 10.13 or earlier) and use Apple Mail as your desktop email client you’re likely to having increasing issues when attempting to connect to Office365 or GMail hosted mailboxes. Put simply, the version of Apple Mail on those older versions of Mac OS don’t support modern authentication standards and hence whilst you might have the correct username, password and server address you just can’t configure them.

The solution is either use a webmail interface to your mailbox, switch to an email client that does (such as Outlook 2016+, Thunderbird, etc ) or upgrade to Mac OS 10.14+(which at the time of writing is supported by all major email providers ).

Apple’s lack of support for older hardware/operating systems sometimes doesn’t compare favourably with Microsoft’s generally much long term support for Windows and their “first party” apps.