Error trying to upgrade to Mojave or trying to install security fix 2018.003 - MacBook Pro 2018 15''

Hi,

I have a MacBook Pro 2018 15'' running HighSierra (10.13.6)

  Nome modello: MacBook Pro

  Identificatore modello: MacBookPro15,1

  Nome processore: Intel Core i7

  Velocità processore: 2,2 GHz

  Numero di processori: 1

  Numero totale di Core: 6

  Cache L2 (per Core): 256 KB

  Cache L3: 9 MB

  Memoria: 16 GB

  Versione Boot ROM: 15.16.6613.0.0,0

I have two issues:

1) I'm unable to install the 2018-003 10.13.6 security update

Whenever I try to install the security update, I get an error.

I tried to skip this update and go straight on Mojave, but trying to install Mojave I get an error at the end of the installation process

What can I do to fix the problem and upgrade to Mojave?