Especially for new users, a sudden inability to type may have been simply a bumping of the tab or mouse-click keys, putting the cursor’s focus in another place. Try clicking back to where you want to type.
If your CharaChorder seems to be acting strangely, unplugging it by the USB cable and re-plugging it back in will force it to reconnect and reboot.
If your CharaChorder isn’t functioning properly, such as if your GTM Menu is no longer showing all of the available options, you may need to reinstall your firmware.