Interesting bit on the current WIKI article:
According to Hitchcock's daughter, Patricia, in a 2005 DVD-released documentary, some critics, after initial rave reviews, gave the film poor reviews because of the so-called "positive" portrayal of the German character in the film. (Today, film reviewers think just the opposite. Critics call the film almost an American propaganda film.) Other film critics caught on to the critical damnation and many writers began giving the film poor reviews. 20th Century Fox executives, under pressure, decided to give the film a limited release instead of the wide release most of Hitchcock's films received. Advertising for the film was also reduced, causing the film to have a poor box office when released in 1944.