Refworks have been under the bonnet of their software again in the last day or so.
They've since put out advice that some users may encounter problems at logging in, and are recommending users "clear their internet browser cache of cookies and restart their browsers".
Initial testing here at Keele hasn't uncovered any problems on the campus network.
However, if anyone at Keele find they have a problem, here's some useful links on how to clear cookies from a variety of browsers:
Internet Explorer (Various)
Refworks Technical Support email is email@example.com