Exchange ActiveSync for Mac OS X and Windows
Once you have enabled two-factor authentication, external applications such as Outlook, Thunderbird, DAVx⁵, or mobile calendar and contact apps can no longer access mailbox using your regular password.
To do so, you need to create an application password. Without enabled two-factor authentication (2FA), the use of application passwords is optional.
Data synchronisation via ActiveSync should only work with mobile devices such as iPhones, iPads, Android devices or BlackBerrys. Synchronisation via ActiveSync with a Windows PC or Mac is officially not possible – ActiveSync was not developed for this purpose.
Although some people may have managed to do so, it is not an officially supported feature and we therefore advise against it.
Note on Exchange ActiveSync
As Exchange ActiveSync (EAS) was developed by Microsoft, it runs smoothly on most Microsoft devices with Microsoft software.
For all other devices (Android, iOS, Linux), the ability to synchronise multiple calendars depends on the implementation of EAS and therefore cannot be resolved or changed by us.
We therefore recommend that our users use the open standards IMAP and CalDAV/CardDAV for synchronisation.
The respective setup for the different platforms is described in detail in our help/FAQ articles.
