Cant connect to office365

I can't connect to Microsofts Office 365 anymore. I have confirmed my account and other folks in my organization dont have this problem. Login in on windows 10 on the same network works. I have also tested on another Mac with same OS and problem are the same. I have tried on iPhone and the same problem.

This is what happens. When I go to portal.office.com I cant enter user/pass and I dont get any further. The URLs are changed rapidly (redirects?) and the last URL that shows up is login.microsoftonline.com

When I connect on other networks like the mobile 4G or my network at home, I can login in on Office365. After I log in on the mobile network, I can use for example OneDrive and online excel with my work network. Looks like the login "survive" a change in network connection.

When I use Chrome an error says the DNS adress of the domain cant be found.

I have restarted browsers and MacBook and run a DNS flush. (sudo killall -HUP mDNSResponder)

I use OS 10.13.1 and Safari 11.0.1 (13604.3.5)