If anyone is having trouble accessing https://scihub.io (the site providing the papers) you can find the site directly at the ip address: https://31.184.194.81/ ... Apparently the domain name was seized. The certificate is for sci-hub.io (safe to accept). Or you can just connect to http://31.184.194.81/ if you don't want to bother with the warnings (and are ok with DOIs and papers being transmitted without encryption).
EDIT:
Their other domains:
https://sci-hub.cc (uses sci-hub.io certificate)
https://sci-hub.bz (uses a separate certificate and ip address -- 104.28.20.155)
And a tor site: scihub22266oqcxt.onion