We setup multi AP using RB750 with same SSID name, different channels.
Alot of notebooks works great with them but one (important one) try to connect to the wrong AP.
It's trying to connect to AP that have bad signal (more walls on road), instead of connecting to the nearest one.

I wanted to 'ban' that MAC address from connecting to the router using Connect List in Wireless Tables.
I setup that this way:
interface: the AP interface
MAC address: MAC of the notebook
Connect: unchecked
Signal: -120..120
Wireless protocol: any
Security: none

Sadly that didn't stoped from connecting to this AP

Am I missing something?

Ap selection is only on the client. Even if you disconnect it, it can decide to join the same ap again and again. So you have to set the client correctly in order to select the right ap...

If you've done this correctly it should stop the client from connecting to the AP. But do it from access-list, not from connect-list.