Unable to install nvidia drivers on Ubuntu 18.04

So I'm trying to install the nvidia drivers for my laptop (it has GeForce 940MX) but without luck.

I'm trying to install them by typing:

 sudo ubuntu-drivers autoinstall

Unfortunately this fails and gives the following output:

Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
 nvidia-driver-396 : Depends: nvidia-dkms-396 (= 396.54-0ubuntu0~gpu18.04.1) but it is not going to be installed
                     Depends: nvidia-utils-396 (= 396.54-0ubuntu0~gpu18.04.1) but it is not going to be installed
                     Recommends: nvidia-settings but it is not going to be installed
                     Recommends: nvidia-prime (>= 0.8) but it is not going to be installed
                     Recommends: libnvidia-compute-396:i386 (= 396.54-0ubuntu0~gpu18.04.1)
                     Recommends: libnvidia-decode-396:i386 (= 396.54-0ubuntu0~gpu18.04.1)
                     Recommends: libnvidia-encode-396:i386 (= 396.54-0ubuntu0~gpu18.04.1)
                     Recommends: libnvidia-ifr1-396:i386 (= 396.54-0ubuntu0~gpu18.04.1)
                     Recommends: libnvidia-fbc1-396:i386 (= 396.54-0ubuntu0~gpu18.04.1)
                     Recommends: libnvidia-gl-396:i386 (= 396.54-0ubuntu0~gpu18.04.1)
E: Unable to correct problems, you have held broken packages.

Can you please explain me what the exact problem is (I'm having some hard time trying to understand it) and what should I do to fix it?