E29 on the Beko B3WFU48215WW ES indicates self-protection due to a supply issue, such as electrical voltage or water pressure. The code does not determine which one is occurring.
What supply changed
The manufacturer documentation groups several conditions under E29. Note whether it coincided with a power outage, no water, a closed valve, or work on the installation. From the outside, check whether the appliance still has power and whether the home has water.
Do not measure circuits or switch outlets with extension cords to test it. If there is electrical damage, a hot plug, or water near the connection, stop using it and request assistance.
Cancel according to the panel
On the documented platform, the manual refers to the section for canceling and selecting another program. Use that operation only after resolving the supply condition and confirming it applies to your model; the buttons vary by series.
If E29 returns with the supply restored, request a diagnosis. The message not appearing after canceling does not confirm a repair. If you saw it in the history, mention that and whether the problem is still happening now.
Explain whether water, electricity, or both were missing: E29 by itself does not distinguish between those conditions.