Version: 2.1.1 (using Devel)
Installed from: Compiled sources
I have some paper as PDF files. When I import them I get a DOI in the title and in the DOI field, but tellico can't look it up.
I have a crossref data source set up (with just email, no password).
I'm assuming it's the same issue as
http://mail.kde.org/pipermail/tellico-users/2009-December/000320.html where you're using an authentication method that Tellico doesn't currently support. I've added the feature for the next release (2.2), though, which should be out in a week or two.