Custom App won't start on Splunk 6.6

Hello, I am facing the problem with starting up the custom app. Custom App is not working under specific condition below. - Splunk 6.5.3 & Chrome -> OK - Splunk 6.5.3 & IE11 -> OK - Splunk 6.6.0 & Chrome ->OK **- Splunk 6.6.0 & IE11 -> Not working** Can anyone tell me what are possible causes and what actions recommended to take? I would really appreciate any advice and help on this matter. Thanks