Membership Broke Protected Content Redirect

Hey folks, I finally took the plunge and upgraded today from to (after the many problems I had with the immediate upgrades after The only problem I've notcied so far is that when a visitor clicks on a protected page (, they get a 404 (see screenshot), not the "Protected Page" content (

This was all working okay before the upgrade and I've walked through the settings post-upgrade but can't see where it's going wrong.

I've already set you up with support access if you want to take a look.