When running the game with a local master the moves triggered from the debug panel raise the following error:
ERROR: disallowed move: moveName
Go to the local master docs and open the example in SandBox
https://boardgame.io/documentation/#/multiplayer?id=local-master
In the Client, set debug to true and reload the app:
https://codesandbox.io/s/boardgameio-dibw3?file=/src/index.js:551-556
Open the developer console.
Select player 0 by clicking on it from the debug panel (otherwise it will raise ERROR: player not active - playerID=[1] as player 1 is selected by default, not sure why):

clickCell move from the debug panel, enter 0 (or leave it empty), and press enter:
ERROR: disallowed move: clickCell
I forked the example project following the steps to reproduce so you can take a look right away:
https://codesandbox.io/s/boardgameio-forked-1yihh
Thanks for the clear report and reproduction steps!
This is actually a symptom of another bug/error: in this case each client is rendering the Debug Panel (one on top of the other). That’s why player 1 is selected by default — because player 1’s debug panel is rendered second and appears on top. We actually need to fix this some other way by rendering one debug panel per _master_ instead of per client (or potentially have some way of toggling between debug panel instances if there are several).
Thank you, the fix worked! I also activated the debug panel only in the first client, as you suggested, and then everything worked as expected. Thanks again!