We changed servers last Saturday around 10 - 11am GMT I think.
There were some posts lost in the reboot and there have been one or two issues reported - some of which have been sorted by logging yourself out and then back in again.
The login issue is something I have experienced lots of times over several years. The first option top left of the main page didn't work, and would throw up a second login and password box centre screen which worked perfectly.
Strangely though when I logged out yesterday to check if a failing admin permission issue I had, would correct itself, I logged straight back in with the top left option.
Bugman has been watching and listening.