After that, when trying to update (apt-get), I could not do it. I do not know if there is a relationship between the two facts, or it has been a coincidence.
Any help or information is welcome.
It is almost a bad idea to manually configure the network when you have DHCP available. You are better off configuring your DHCP server to always give the same IP address to that RPi instead.
In all likelihood you either didn’t configure the gateway IP address or subnet mask correctly or you need to manually configure your DNS servers as well. Without DHCP, you have to configure DNS manually too.