Family Historian User Group

There does appear to be an 'athens' access link on the 'sign in' page.
Knowing nothing about this term. How does one obtain a an athens ID. Is it restricted to HE or FE sources?

I have just spent most of the weekend on this site with great results. However I cannot access the site this am. Does anyone know if the trial is over as a whole or just my trial period?
Has anyone any tips for getting permanent access please