How many USB ports cubase recognizes

I thought I should just defer to questioning the forum rather than go through details in the manual to find out how many USB ports cubase can recognize simultaneously. Right now I have two different midi controllers and an audio/midi interface. In total that is 3 USB ports I am using to interface with cubase. When they are all plugged in I start up cubase and the two midi controllers hooked up don’t send messages that i should see. Midi input is either on “all midi” or I’ve even tried with only one selected. Nothing is detected! So, I figured that it maybe has something to do with the number of usb ports cubase will recognize? idk. The audio interface is working fine just the midi controller won’t send messages.

The number of usb ports is not the problem. Have you swapped stuff to different slots to check if the ports are faulty?