For Hoover Dynamic Next, the official E04 guidance points to checking for too much detergent. If the water inflow does not stop, prioritize the supply and request assistance.
Suds after dosing
The manufacturer documentation asks you to check whether too much detergent was added. Note the product, concentration, and amount, along with any additives or pretreatments. A dose meant for a full load may be excessive for just a few garments.
Follow the recovery procedure in the manual and let the suds subside without adding homemade defoamers. Do not add more detergent to try to finish the cycle. The Hoover Dynamic Next index helps distinguish E04 from intake and drain warnings.
Water continuing to rise
If you see continuous filling, a rising level, or overflow, close the accessible tap, stop using the machine, and request an inspection. Do not assume everything is due to detergent, and do not repeatedly reset it with the supply still open.
If E04 returns with the correct dose and no visible condition you can correct, report the Dynamic Next model and when it appeared. The warning does not by itself prove a faulty solenoid valve, and it should not be applied to every Hoover family.
Record suds and water level as separate observations: they can lead to different decisions.