AD user is assigned to role SPLNK_DNS which is working fine. User also needs to be part of other role called exchange. Splunk Manager UI shows that user is part of both roles and no erros in AD logs when user logs it. However, when he searches for exhange logs, no events shows even though events are there.
Also noticed that if role SPLUNK_DNS is removed from this user, he is able to search the the exchange datatype with results.