Getting Bumblebee to work on Dell e6420 with KDE Neon

[ghost]

Dear Bumblebee devs,
First of all thank you for your efforts on this piece of software.

I've been trying to get my optimus setup recognized with linux but failed to do so. I previously used Kubuntu 18.04 but got to reinstall everything following a suspend bug (black screen) that I could not debug. I decided to go on with KDE Neon which is based on the same LTS version.

Setup is a Dell Latitude e6420 with Core i7-2760QM with a Nvidia GF119 [NVS 4200].

I followed the install guide for Ubuntu : https://wiki.ubuntu.com/Bumblebee

When running the command "optirun firefox", I have the following error:
Cannot access secondary GPU - error: [XORG] 'EE) Failed to load module "mouse" (module does not exist, 0)

Any help would be welcome !