Symptoms
An error occurred trying to authenticate the user
System.DirectoryServices.ActiveDirectory.ActiveDirectoryServerDownException: The remote procedure call failed. Name: "[DC]" at ...
Diagnoses
This error appears every time a user logins to K2 designer/runtime for the first time every day. After refreshing, the error disappears. It seems like K2 is trying to resolve every DC
Resolution
A coldfix was provided which supports the key added in the Windows STS Web.config to disable group resolution. Please contact K2 Support to obtain this coldfix.