Sd and SUD indicate excessive suds in the documented front-load Brastemp BNF15. The pause or extension of the cycle may be part of its suds reduction routine.
The BNF15ASANA manual confirms both alerts and describes a recovery process for the appliance. They do not automatically apply to every display on the brand.
Let the intended routine take effect
If there is no leak or other problem, let the program continue according to the manual. Do not add product to neutralize the suds, and do not chain together restarts to shorten the wait. If water appears outside, stop using it and address the leak before continuing.
Check that the detergent is suitable for front-load machines and that you measured the dose for that load. Formulas have different concentrations and sudsing levels; a normal amount may be excessive after switching products.
See suds control and detergent use to adjust the habit. If Sd/SUD returns after correcting it and completing the authorized maintenance, seek assistance, without assuming that a restart removed the cause.
Record the product, amount, and load when it happens again; this helps assess usage before attributing the pause to a malfunction.