(Click to enlarge)

This will be some kind of server setup error. See screenshot of it working (the domain in the screenshot isn't mine, I just used my hosts file).

I did have to configure the cookie domain, but that's it.

Ok, this actually related to the size of the block cache. I think changing the domains caused the cache size to grow, and that caused a memory error.

The next beta has a big optimisation for menu blocks, which I have deployed for you. This solves the problem.