With harmon.ie, you cannot access personal OneDrive/My Sites that are configured with a custom host.
Your SharePoint administrator configured the SharePoint OneDrive/My Sites with a different host than the other SharePoint sites. For example, the SharePoint site host is domain.com, and the OneDrive/My Site host is mysite.domain.com. harmon.ie cannot detect the OneDrive/My Site host setting and uses the standard SharePoint host URL.
Specify a mapping between SharePoint host URLs and OneDrive/My Site host URLs.
For each mapping, add a new String Value to the MySiteHostMapping registry key. To learn how to do that, read Provision harmon.ie for Outlook to all users.
Use one of these methods:
The Domino administrator can provision the URL mapping from SharePoint to OneDrive/My Site using Managed Settings. For information about how to deploy this setting, read To set default values using Domino.
Add each mapping as a separate item, using this format:
|/mysiteurl.<SharePoint host URL>||<OneDrive/My Site host URL>||com.mainsoft.sharepoint.sidebar|
Notice the leading slash in the item name.