Outerwall Inc. US:OUTR fell 22% early Tuesday, trading at its lowest level in more than two years, after Monday’s disclosure of problems at its Redbox unit — yet another physical business under assault by digital streaming.

A disappointing revenue outlook for Redbox, whose red vending machines offer DVD rentals starting at $1.50 a day, shows that new movie titles and the addition of more videogames have not been enough to stave off the challenge posed by streaming rivals such as Netflix Inc. NFLX, -4.18% , which also still rents out physical DVDs by mail. Outerwall, formerly known as Coinstar, said that Mark Horak, the president of Redbox, will be stepping down and replaced on an interim basis by Erik Prusch, Outerwall’s chief executive.