dconf - Custom icons are not displayed in the panel menu

The custom icon custom-symbolic.svg is not displayed in the panel menu.
This is a segment of a dconf file:

[org/cinnamon]
app-menu-icon-name='custom-symbolic'

The full path to the file I created is:

/usr/share/icons/hicolor/scalable/apps/custom-symbolic.svg

and has a resolution of 51x51 pixels.

The owner and permissions of that icon are identical to those of all other icons in that path.

If instead of custom-symbolic I insert cinnamon-symbolic, which is present at the same path, the panel menu icon is displayed correctly, as well as all the other icons already present in the path:

/usr/share/icons/hicolor/scalable/apps

What I did wrong?

I solved:

sudo update-icon-caches /usr/share/icons/*