Hi Guys,
I have the same issue. I can login when I use Firefox or Chrome but when I use IE9 I get the same error as Chris ("An invalid ArcGIS Portal URL was entered. Please verify the URL."). I have performed the certificate suggestions but still no joy. I need to have this working in IE9 asap so any ideas would be hugely appreciated.
Version I'm using is v3.0.1 on Sharepoint 2013
Cheers
Paulg