K-9 uses WebDAV to communicate with Exchange. As of Exchange 2010, WebDAV is no longer supported. For this reason, K-9 is unable to work with Exchange 2010 at this time. It will be a major effort to correct this issue.
These instructions apply to K-9 version 3.401 and later. Please see below for the original instructions that apply to versions prior to 3.400. Versions prior to 3.401 are known to have issues with Exchange.
The parts of K-9 that connect and authenticate with Exchange were rewritten in version 3.400. These changes were tested with Exchange 2007 using form-based authentication. The following is a basic description of these options. For a more in depth discussion of how K-9 communicates with Exchange, see the following blog post.
The following options are "advanced" options, and users should not need to change them from the defaults.
NOTE: Setting your 'OWA path' to "owa" is incorrect! If you enter values into either 'OWA path' or 'Authentication path' and then open an issue, the first thing I will tell you is to leave them blank. Please, save me the trouble.
If you receive a 501 error in your logcat output after K-9 authenticates successfully, try setting your 'Mailbox alias' to your email address. Note that WebDAV is not enabled by default on Exchange server 2007, and must be enabled for K-9 to work. If you receive a 403 error in your logcat output, chances are WebDAV has not been enabled.
K-9 Mail is only known to work with Microsoft Exchange 2003 with "basic authentication". If you have configuration advice that you can provide for other environments, we'd appreciate the contribution.
Let's say this is how you login to the Exchange webmail interface / Outlook Web Access:
You can tell if it is basic authentication if a dialog box appears for the username and password. If the login is just on a web page, without a dialog box, then your site uses form-based authentication. (It is currently unknown if the guidelines given here work with form-based authentication.)
Once you login, you will see the browser show a URL like:
OK, here's how to configure K-9 Mail:
The word "exchange" in the "WebDAV (Exchange) path" is copied from the last part of the URL shown in the browser when you login to Outlook Web Access the normal way.
These alternate instructions were submitted in issue 1631 by Der.Harry.Karl.
owa/auth/is the path and
logon.aspxis the handler.
Testing this with some other Exchange setups I could find out that especially failing to enter the right auth path leads to errors. Another vaild entry I found was:
These alternate instructions were submitted in issue 1990 by Docsmooth2486.
If you have hosted Exchange, and after setting up no custom settings for WebDAV or "Mailbox" path, you receive a "HTTP 501 Not Implemented" error, your WebDAV path is likely wrong. To check this:
email@example.com remove the "@": userdomain.com
/userdomain.com/Inbox(entering your modified email address after the
/exchangepart) to the end, so the full path reads something like:
/exchange/userdomain.com(using your modified email address)