Menu sidebar height on small screen resolutions

I'm currently having a challenge on a SaaS I'm helping designing, regarding small screen sizes.

That SaaS has a menu sidebar on the left as its main navigation, with 2 levels of navigation.

The problem with this sidebar is that when it's visualized on small screen sizes (1366x768 to be exact), all the items on the navigation sidebar don't fit, making the last items disappear.

My question is: do you know a good practice or idea to solve this issue, so all items on the sidebar are visible on small resolutions?