I have already built one network using pro-sites, so have got it working fine.
However the one I am building now, I have a strange issue and wonder if it has been come across before, so I can avoid stepping back and rebuilding from scratch.
When going to 'account' or 'pro upgrade' i.e. linking to something like /wp-admin/admin.php?bid=9 depending on the bid , if I am logged in I get just a blank screen, and if it it done as part of a 'create blog' process, which works fine, but step 1 of loging in also goes to /wp-admin/admin.php?bid=9 except instead of a blank screen, I get a redirect loop error from my browser.
I have put full error setting into functions.php which would normaly show up if a blank screen was due to a php issue, but I get nothing.
So the redirect loop seems to be where the problem may lie.
Any thoughts ?