After update of the PI Integrator for Business Analytics from 2016 > 2016 R2 > 2018 the portal website show a full gray screen in IE11.
In Chrome it is working fine.
Found it sooner than I thought!
It is in IE11 compatibility settings. While looking with F12 there was an error; "The value of the property 'webpackJsonp' is null or undefined, not a Function object".
The trick was unchecking the checkmark for; 'Display intranet sites in Compatibility View", while using the FQDN or localhost url.
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