Can't update a file

[ingolfured]

I'm trying to update a file in the following way:

file = directory.files.create(key: "justtesting", body: "some body")
file.body = ""
file.save

However, this returns me

Fog::Storage::Rackspace::ServiceError: [HTTP 503 | tx2a7abaa345d14c9898cc1-0057754df5lon3]

Everything is fine when I do

puts file.inspect 

(before the file.save though).

Any ideas? In the documentation it says only some objects can be updated. How do I know which one it is?