We are phasing out Zendesk. Please see Discourse instead: https://community.getmailspring.com/t/exchange-with-mailspring/303
Unfortunately, Mailspring does not support Exchange (Exchange Web Services or ActiveSync.) We're looking to add support in the future, but Exchange is a separate email standard and we expect it will take time to develop and test Exchange support.
In the meantime, you may be able to connect to your Exchange server via IMAP. Note that not all Exchange versions support this feature.
For a full list of the providers Mailspring supports, click here.