Publishing iCalendar files, and subscribing to server hosted iCalendar files


When using the configuration and link advice settings in the Online MailEnable Webmail Users Guide (Calendar Management Section) a configured calendar is not being published or is not shown when loaded.


The most likely cause of this problem is that either the Synchronization service ("Synchronization" node in the admin console) is not contactable, the CalDAV/iCalendar support feature has not been enabled within the MailEnable administration program or the URL configured in the client is incorrect for the service. 


To overcome the above issues use the following steps;

1.  Ensure the MailEnable HTTPMail service is running by navigating to within the MailEnable administration console to: Servers > Localhost > System > Services Status. The Synchronization service also known as the "HTTPMail service" is the one that accepts and processes the connections from a client configured to publish iCalendar and synchronize CalDAV calendars.

2.  Ensure that the port for the Synchronization service is enabled and allowed access through any proxies or firewalls. The default port is 8080. Default SSL port is 8443 (not enabled by default).

3.  Enable the CalDAV/iCalendar feature in the administration program. Navigate within the administration console to: Services > Localhost > Services and Connectors, right click on the CalDAV/CardDAV icon and select Properties from the popup menu. Then make sure that the "Enable CalDAV support and iCalendar hosting" checkbox is checked.

4.  Restart the "Synchronization" service by right clicking on the Synchronization node under: Servers > Localhost > Services and Connectors > Synchronization and test again.

If this does not work then you should ensure that the URL that you are using in the client to connect to the server service is correct as per the instructions in the MailEnable Webmail Users Guide (Calendar Management Section).

When configuring a client for iCalendar/CalDAV it can be hard sometimes to work out what is going wrong as the clients tend to not return enough information when configuration issues are present. 

You can check the MailEnable Synchronization logs to see if the client is connecting to the Synchronization service each time you try to connect using an email client.  If you do not see connections from your client IP address in the Synchronization activity log in the appropriate day of your test then you are not able to connect to the service and should again review the steps above.


Here is some more information to compliment the supplied details in the MailEnable Webmail Users Guide. The information here is more specific to configuring a client and breaks down the differences between iCalendar and CalDAV configurations.

Microsoft Outlook

Outlook only supports posting/retrieving iCalendar files from the server.

The mailbox must allow anonymous connections to the calendar. A restriction with Outlook is that you are not able to edit any of the calendar items.
   These can be used to access a MailEnable calendar:

   These are used to access a specific published file
   Can publish an ICS file or publish to a mailbox calendar

   These can be used to create an ICS file on the server
   These will publish the calendar items into the MailEnable calendar   

   You cannot specify the filename like the URLs below. Outlook will determine the filename when it publishes.


   - When removing a calendar from the server, if you are connected to a MailEnable calendar it will not remove the entries
The last component of the URL must be either a / character or a string with no . character in it.
    - If publishing to a MailEnable calendar, Outlook will give an incorrect URL to it, since it is assuming it is going to ICS file
    - If you publish an ics calendar, if that calendar is changed by other subscribed users, then Outlook will not recognise the change, and any further updates on the Outlook client will overwrite the server file again.

Thunderbird with Lightning Plugin 

Thunderbird can connect using iCalendar or CalDAV to MailEnable via the HTTPMail service. When using Thunderbird, be aware that it will cache passwords used to access URLs. If you clear the cached passwords under Options, you will also need to exit and restart the Thunderbird application. You cannot use the CalDAV protocol to connect to a published iCalendar file.

   This URL can be used to authenticate as a user and connect to a MailEnable calendar (use CalDAV setting)
   These can be used to access a specific MailEnable calendar (use CalDAV setting)

   These are used to access a specific published file (use iCalendar setting)

 Can publish an ICS file or publish to a mailbox calendar

   These will publish the calendar items into the MailEnable calendar (use iCalendar setting)  

   You must use a full filename with Thunderbird otherwise it will be published to the MailEnable calendar

Configuring permissions for calendar access

When accessing a MailEnable calendar, the permissions are configured under the mailbox shares options in webmail. The "Calendar" folder must be shared and permissions can be set. It is the same as configuring sharing for other webmail users.

For ICS file hosting, the permissions can be configured for the mailbox as Read only, full, or no access. This applies to all the hosted ICS files, and is configured under the sharing options in webmail. Anyone logging in with the mailbox username/password is not affected by these permissions.


Product:MailEnable (Ent-Any)
Class:TRB: Troubleshooting (Configuration or Environment)
Revised:Thursday, June 25, 2020