I prefer: nec clientes nec patrones dormiunt
I look forward to learning how to say: Patrons and clients seldom sleep when in bed together. Or am I expecting too much from Duo?
I put "The patrons and clients do not sleep." Will someone explain why it's not correct?
Unless you had a typo you didn't notice, it should be accepted. Report it if it ever comes up again.
FYI: "The patrons and clients don't sleep." -- the contraction is the only difference -- was accepted just now.