Interesting.<br><br>No, I definitely haven't disabled cookies. It works fine with *every* other site I visit. I've checked that the cookies for this site haven't been individually disabled in the Cookie Manager. And I've also run the Linux version of Mozilla with a completely fresh setup (i.e. it had never ever visited this site before, and had not had any options configured) and it still fails the same way.<br><br>But it does look like Mozilla is behaving *as if* cookies were disabled. By monitoring the cookie file as I attempt to log in, I can see that it isn't even attempting to write the cookie.<br><br>Thanks for the input. The fact that it works for you guys helps me narrow down the problem. I'll probably have to grab the source code and debug the browser from scratch! Sounds like an obscure bug.