It seems the Sophos firewall at work blocks all access to lemmy instances.
Join-lemmy.org and lemmy.ml are blocked completely. I can see the front page on sh.itjust.works and lemmy.world, but clicking on a post results in an infinite loading circle. When I try to log in on either site I also get a loading circle on the login button.
Any ideas if I can circumvent the firewall?
Those blocked URLs are in Finland and France, respectively. Your admin is likely using the geo-IP “country blocking” feature of Sophos UTM or XG. Without a VPN, you won’t be able to get around it, directly, but federation means you don’t have to. Whichever instance you can reach will be able to pull content from the ones you can’t on your behalf.