SSRS and PowerBI Report Server on same server

I've just installed the August 2018 release of PowerBI Report Server onto the same Win 2012 server with SSRS 2016. I can get it running but it clashes with SSRS with URL reservations. I've configured them to use different Virtual directories and ports but SSRS keeps breaking. - SSRS: http://ServerName:80/Reports - PBIRS: http://ServerName:8080/PBIReports What have I missed? Edit: I have SSRS 2017 and PBIRS working at the same time on my laptop. Both on Port 80 but with different virtual directories.