on 23 Nov 2017 22:33:58
If people are having too many Active Directory Groups, e.g. very experienced top management then it might happen that the October release of Power BI Report Server cannot serialize the authorization header.
The user will experience only "Error 400 - Authorization header is too big"
The problem is stated - and hereby I confirm - here: https://www.qumio.com/Blog/Lists/Posts/Post.aspx?ID=52
You can run into REAL trouble if you want to present a solution you tested before with a lot of people and it fails because a manager has too many AD groups.
I changed the registry settings according to the manual and now everything works as expected.
best regards, Sebastian