In our to level site collection (which is a portal), and I've set the search center to my enterprise search site collection: /sites/search/pages. When I log in through ADFS and try to search anything with search box in top-right corner, I'm getting 'access denied' error.
But when I'm logged in as site collection administrator through active directory from intranet, I can perform enter search term and I'm taken to results page, but unfortunately it is always empty. Funny thing is, that when I search same term from this result page after changing selection from 'This site' to 'All sites', I'm taken to the search center results page and results are displayed correctly.
I'd also like to enable anonymous users to perform search from on our top level site collection, since anonymous access is active. I enabled anonymous access on search center site collection, but still I'm asked to log in when I try to perform search from site collection. I can perform anonymous search directly from search center, and results are correctly security-trimmed.
How can I solve those issues?
EDIT 1:
Our platform is SharePoint 2010 Server Enterprise.