WebDAV is Unavailable or Responds With Errors

  • Updated

For Exchange 2007, Exchange WebDAV Services are used in combination with the Exchange Web Services (EWS) to provide additional capabilities not yet supported by EWS.

For Exchange 2010, WebDAV is no longer available and all functionality is supported by Exchange Web Services.

By default, with Exchange 2007, Riva attempts to access the WebDAV host on the same server as EWS (the CAS server).  In standard Microsoft Exchange deployments, the CAS server is responsible for relaying WebDAV requests to the appropriate internal mailstore.

Note: To know what the proper WebDAV host is for your mailboxes, contact your organization's Exchange admin.

Note for Exchange Admin: If the CAS server role is on the same servers as the mailbox role, Exchange does not properly relay the requests to the appropriate mailbox server.  For the ability to add multiple alternate WebDAV hosts, contact support .

Side-effect of Missing WebDAV

None of the "core" sync functionality in Riva is affected by the WebDAV error. 

WebDAV is used to enable two features to increase usability:

  • Adding Riva-specific Outlook categories to the "Master Category List", so that it appears in the Outlook client in the default list.
    To overcome this limitation, each user can manually add the configured category to their own Master Category List in Outlook.

    Outlook2010-AddCategoryToMCL (1).png
  • Adding Riva-specific column headers available to be displayed (Probability, Revenue, Next Step, Close Date, etc.)  for the Outlook Windows client to support Riva's advanced integration with Opportunities / Cases / Quotes (if the modules are enabled).  

Override the default OWA / CAS WebDAV Host

WebDAV is usually accessed by connecting to the OWA / CAS server with a folder path of:  /exchange/{user}@{domain.name}/

If this configuration is non-standard or is different, the default WebDAV host can be overridden on the Exchange connection in Riva:

Webdav (1).png

Handling Different Authentication Methods (Forms vs. Basic)

Microsoft provides two major means of authentication for WebDAV:

  • Forms Authentication
  • Basic Authentication

Because Riva does not know which authentication method is used, Riva always sets the Basic Authentication credentials and initiates a Forms Authentication logic request.

For Forms Authentication, a request is made to the host server address on the following path:  {server-host}/owa/auth/owaauth.dll

To disable Forms Authentication:

Working around a broken CAS / OWA redirection

Each mail store can be configured to have WebDAV directly accessible.  If the automatic redirection of WebDAV via the primary CAS OWA does not work, a workaround is available.

A comma-delimited list of servers can be specified, and Riva will attempt to connect to each host to find and set the master category list of the user.

To enable this feature:

  • Set the following App.Setting (in the file: Omni.Crm.CrmAgentEx.exe.config):

    Key:  Sync.Ewd.AlternateHosts

    Example value:  https://ex-mbx03.company.local,https://ex-mbx04.company.local,https://ex-mbx05.company.local

WebDAV Error Message

Log files showing the following error would indicate that the WebDAV services are unavailable.

Unable to load Master Category list. Please ensure you have Full Access permissions to the user's mailbox.


Followed by:

System.UnauthorizedAccessException: Request Failed! The remote server returned an error: (401) Unauthorized.





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