Symptoms

Impersonate throws 28026 K2:DOMAINUser does not have permissions to impersonate user DOMAINUser
 

Diagnoses

The issue with impersonation is happening in our environment - Error says " 28026 K2:DomainUser does not have permissions to impersonate user DomainUser"
The following check is already done.
1.Service account which the Website app pool is running is already added in K2 workspace Rights with full rights with impersonation and admin rights.
2.The Website ASP.NET Impersonation and Windows authentication enabled with web config having ImpersonateUser=True

This is our code
SourceCode.Workflow.Client.Connection con = new k2client.Connection()
con.Open("K2 Server Name")
con.ImpersonateUser("domainuser")

Please get back to us on this as soon as possible.
 

Resolution

Please disable "ASP.NET Impersonation" and enable only "Anonymous Authentication" and "Windows Authentication". Regarding the "ImpersonateUser" previously mentioned in the web.config. I believe "ImpersonateUser" is a method of the "SourceCode.Workflow.Client" API. Are you using code similar to:

http://help.k2.com/onlinehelp/k2blackpearl/DevRef/4.6.9/default.htm_Working_with_a_Process.html?TocPath=Runtime%20APIs%20and%20Services|Workflow|Workflow%20Client%20API|Workflow%20Client%20API%20Samples|_____2