Around 2015 FEB, the NP2 login system changed away from Google social login.
But once logged in, there is another email address in your account settings that receives notifications of game starts when all player positions have joined in, or notifications from your in game new email threads that another overlord has sent to you.
I suspect this internal email address can be different from your Google social log in.
So did you use a different email address for gaming ? I am just guessing.
I do not know whether these two forum threads would help you ?
If these ideas are no help, then wait and @JayKyburz will check this and help you.