I have the same issue and I think this is because the developer preview builds are not certified by google. (They have to run/pass some kind of test suite to get it certified) and I think that'll only be done in the final build.
Download the app here and install https://help.netflix.com/en/node/57688?ba=SwiftypeResultClick&q=Netflix%20says%20%27Device%20failure%20occurred.%20(501.-117)%27 . It's not supporting download so this the only problem with this version.
PS disable automatic updates in play store in order to use it until official android P is released