Symptoms
When we are trying to search users (for example, when redirect task) and set the domain to All, no results were found but Anonymous.
When we set the domain filter/search to the default domain and set the search user box empty, only several users on this domain were found, but when we specify the user/search by their account on this domain, it works well.
When we set the domain filter/search to additional domains, no users were found, only Anonymous.
Diagnoses
We checked that only the main domain was added in Workspace, the sub-domains were not registered in K2.
Resolution
1. Add the sub-domains under the User Managers > K2 > Domains in Workspace
2. Modify the Workspace web.config file. Add the connection strings and membership providers for the sub-domains.
3. A k2 service restart is required after making the changes.
Reference:
http://help.k2.com/onlinehelp/k2blackpearl/icg/4.6.9/webframe.html_After_AddingMultipleDomains.html