You don't need to use the modmanager for promods on mp just have them in the mod folder and it doesn't support the trailer packs or interior just the promod map + middle east addon
I had same problem today but using a controller , fixed it by using compatibility mode "windows 8" and run as admin for truckersmp application - try it and see if it works for you
Press tab button then right click so it shows the mouse - overhead you will find the CB radio in truck, there is 3 knobs on there... click the leftmost knob to switch it on and off