I've successfuly exported this app to an .ipa before, and since then i haven't changed the project at all, yet now the .ipa build is always failing.
Earlier today, trying to export as .ipa would bring me to the build page where it would never get anywhere - no build. no error.
Trying it right now, without having made Any changes, the build fails after the first refresh, with the very unhelpful message "Most likely build error cause: An error has occurred."
Again, this is a project that was built for iOS before and nothing changed since then, so I have to assume there's something wrong on your end?