The pane opened, but every button answers “Not connected to Excel”. This means Excel could not finish starting the add-in session, and it is almost always a network hiccup: Excel on the web needs a stable connection, and desktop Excel still talks to Office’s add-in runtime over the network while starting a pane.
Fix it #
- Open the menu (top left) and click Reload add-in, or close and reopen the pane.
- If it keeps happening, check your internet connection and restart Excel.
- On Excel on the web, a stalled browser tab can hold a dead session: reload the browser tab itself.
Why the buttons still answer #
The pane deliberately never sits there looking healthy while being dead: if Excel has not answered within a few seconds, the selection line says “Not connected” and every click explains itself instead of doing nothing.
Still stuck? Contact support and paste in the diagnostic info from the About view.