No Messaging Notification And 'mi Messaging' Notification Toggle Greyed

Aug 23, 2016

I recently changed my carrier and sim card and noticed that, even since, I get no messaging notification.

I am using the default 'Mi Messaging' app.

When I go into settings, App notifications, messaging, the 'show notifications' button at the top of the page is greyed and cannot be toggled out.
I have checked and my apps are NOT locked through the App lock setting menu.

I do not use any other messaging app, just the stack Mi Messaging system app.

Any help would be greatly welcome.