AC, AC6, and AE are among the documented communication errors in Samsung washers. The suffixes may identify different connections; the code by itself does not point to a board to replace.
The Samsung chart brings together several internal communication messages. Do not confuse them with losing the phone's Wi-Fi connection or with an in-progress cycle.
Record the sequence without opening the machine
Take a photo of the full code, including spaces and numbers. Note whether it appears as soon as the machine turns on, when selecting a cycle, or after running for a while. If the panel alternates messages, keep the order.
A power reset allowed by the manual may resolve a temporary issue. If AC returns, repeating shutoffs does not verify the status of the link between modules. Do not remove covers to reseat connectors or replace a board by comparing it with another machine.
Also report whether the wash was still running or had stopped and whether there was a prior power outage. These are observations for diagnosis; they do not let you assign the fault to an update on your own.
Support needs the exact suffix and the platform reference to identify which communication it should check.