I am having log in problems as well. I tried from a desktop, laptop and iPad on two different 7.6 forums, one being this forum. When I hit "log In" I was routed to the forum summary page - I could not access the log in page. Someone suggested trying a different connection, so I used my mobile hotspot and log in worked!

Here's a fix. If you disable "stop forum spam" the log in problem is solved. This is 100% reproducible.