Issue
No results are returned when trying to search for users on K2 Management. This happen in any pages that uses the user search, such as when trying to search for users to assign server or workflow rights, or when searching for users to configure Out of Office.
Resolution
If you only have 1 domain in K2, you can use the 'User' SmartObject from the 'AD Service2' service instance to check if you can retrieve users from your domain. If you cannot search for users, then it is likely something is wrong with the connection between your AD DC and K2 server. You can check your domain's LDAP path with a 3rd party tool such as 'LDAP Admin' to see if the LDAP path is working.
If you have more than 1 domain in K2, if K2 cannot connect to the second domain, then it will in turn affect the user search on K2 Management. The reason for that is the user search will look through all the domains you have added to K2. If there is some issue with a domain in the list, the user search will just stop there and nothing gets returned. You can use a tool such as 'LDAP Admin' on your K2 server to check if the LDAP paths to your domain are working correctly.
If there are issues with your LDAP path, please contact your IT or infra team to get them to look into this as this is not a K2 issue.
