On selecting Fab tab within Unreal Engine 5, a page appears, Oops! Something Went Wrong!, and none the page links work.
This includes, Help Center, contact support and take me home.
I have been ripping my hair out of my head with this same issue. I have tried everything from rebooting, to allowing blocked apps through firewall.
I do not how to repair this issue, but one thing I did realize that this is a project related issue. I opened a different project on the same engine version and badaboom the plugin worked again.
Sadly this means I need to start over my project. I am not sure if I should try to migrate some stuff, like maps from the faulty project or just start fresh.
Hopes this helps anyone else banging their to a wall with this issue. It sure almost drove me crazy.