New User Roles Not Working

For some reason adding any users Below SuperAdmin & Admin redirects to a 404 page on my multisite.

It was not like this before and Ive been trying to setup some Editors & Contributors now
as I am finally ready and secure for my launch.

Can someone please help me figure out why that happens?

It accepts the login credentials but just redirects to a blank page on the front end, does not let the users enter the dashboards as it should.

Please Advise !!