I recently downloaded a great new mail app for Mac called Airmail. You can get it on the Mac App Store.

Setting it up with an Office365.com company account is a little finicky. Here are the settings I used to get things working.

Airmail settings
Airmail settings — Live-source image, saved October 12, 2026. Referenced article-size variant; historical equivalence unverified.

IMAP

Username your full email address name@company.com

Incoming server: outlook.office365.com

Port: 993, Full TLS

PLAIN

SMTP

Sending server: smtp.office365.com

Port: 587, TLS

Username: your full email address name@company.com

Password: your password

LOGIN

Then start enjoying your great new mail app!