Fail to Create App by WAB on IE 11

[MatsHardy]

I have set up a Portal 10.5.1 server, I have also federated the ArcGIS Server 10.5.1 to the Portal and created maps on Portal.

When I created an app from the map by WAB in IE, the Web AppBuilder just hung, the IE reported the following JS errors:

1. Cannot retrieve the property 'value' from undefined or null
2. The object does not support the property or method 'startsWith'

But WAB works in Firefox and Chrome. Are there anything missing or I need to configure?

[RobertScheitlin__GISP]

Mats,

   Are you running IE in compatability mode? 

[MatsHardy]

No, IE is version 11 and not in compatibility mode