If the icon is shown on your Desktop, try de-selecting, then re-selecting the appropriate "Show" option in  Finder > Preferences > General.

If it’s shown in your Finder sidebars, try de-selecting, then re-selecting the appropriate "Show" option in  Finder > Preferences > Sidebar.

Try a "Full Reset" as in item #A4.

Try a Back Up Now  from the Time Machine icon in your Menubar, or by control-clicking (right-clicking) the Time Machine icon in your Dock.