How to use Geary with DavMail to access Office 365 email?

[ijonic (Jon Geiger)]

Hello all! I’m relatively new to the worlds of GNU/Linux and GNOME, and I’ve got a dilemma:

My university uses Office 365 servers for email (with 2-factor authentication through Duo), and the only “officially supported” email client, according to our IT department, is Microsoft Outlook. I’ve been playing around trying to get other email apps to work, and the only one I can get working to which someone may know a solution. properly is Mozilla Thunderbird, as well as Evolution, through DavMail. I followed the tutorial here on how to set up DavMail with Thunderbird.

Despite these two clients working (with their own respective issues), I LOVE the Geary UI/UX. I love how easily it integrates with the GNOME online accounts, yet I can’t seem to set up my university email with the IMAP/SMTP settings provided in the settings.

When I attempt to use DavMail to sign in to my Office 365 account on Geary, I get the following notice:
(DavMail Settings included to the left)

Is there some way I can properly tune my settings to make this work, or could there be some support for this sometime soon?

[PowerUser64 (Blake North)]

I’m having this exact same issue with Geary and Gnome Accounts. I have tried all conceivable combinations of the provided options. I have a sneaky suspicion that the issue lies in the fact that DavMail uses a self-signed SSL certificate for encryption (although communications between the email client and DavMail are all internal and do not leave the computer, so encryption doesn’t really matter). Answering whether Geary/Gnome Accounts accepts self-signed certificates is probably a good first step to solving this, especially speaking I have noticed the easiest way to mess up this configuration process in other mail clients and get similar garbled “BAD REQUEST” messages in the DavMail log is by playing with the SSL/TLS settings.