dn indicates an update download on Samsung models that include this feature. During the process, the controls may not respond; power must be kept on so it can finish.
The official Samsung help identifies dn as an update state. It is not an instruction to restart the washer or a diagnosis of a failed control panel.
What to do while it is displayed
Leave the appliance on and avoid changing programs or unplugging it to clear the screen. The Samsung USA help consulted places the download at around 15 minutes; use the timeframe in the manual if your reference gives a different one. Also keep the network connection available.
The same help recommends support if dn lasts more than 30 minutes with continuous power and no Wi-Fi issues. If that happens, note when it first appeared and check before performing resets or power-off cycles. Do not share your network password when documenting the issue.
If the actual text is AC6 or another internal communication code, keep it as is: not every lack of response should be interpreted as an update. A timing coincidence with a network problem also does not prove that the electronics are damaged.
To request support, provide the model, elapsed time, and whether the connection remained active; this helps determine whether the download is still within expected behavior.