A recent change in 3D Warehouse has indirectly led to cases where if you search for something in the Components tray/panel, you will see a message about there being no Internet connection.
The message is misleading, as there most likely is a good Internet connection at the time. What really is going on is that downloading models directly in Components now needs you to be signed in, as was already the case for the 3D Warehouse window.
If you are using SketchUp 2019.2 or earlier the sign in options will show one for signing in with Google, but that won’t work (Google removed that ability nearly three years ago). The sign in with Trimble, Apple, and Microsoft, all should work ok.