In the lower left there is a field called “Root Note” that you have set to C1. That sets the low starting note for where Remote Keys can be set. So if it is C1 that means you can’t enter anything below C1. Set it to the default C-2 and you can assign any note as a Remote Key.
Just want to make sure you (and anyone else reading this) aren’t creating busywork for yourself. The only reason to setup Remote Keys is if you intend to play live and change articulations by hitting keys on your midi keyboard. If you are not doing that you can just leave all the Remote Key stuff blank or set to the default. Also if you do use Remote Keys they do not have to match the VSTi’s Keyswitches. You could, for example, have an articulation triggered by D#-1 and if you set the Remote Key to C8 then that key on the far right end of your midi keyboard will trigger the D#-1 articulation.