How to block PMs by default and ask for user permission

[DankiestCitra]

I am trying to look for a way to keep PMs closed, and when someone PMs me, there should be a request which I can either accept or deny.
After some digging, I found the user command UMODE.
I changed UMODE to %n &2 +g in the user commands list, and set umode %n &2 +g to the connect commands for that server.
However, users are still freely able to private message me regardless of who they are (registered, unregistered, etc).

How can I fix this?

P.S. I am a complete IRC noob, can someone pls provide directions here?