The same here, not good news in the e-mail.
It's kind of annoying there is indeed no further information given about the why and how.
It blows anyway failing an interview, in my opinion.
I'd rather failed the first, second or fourth test then, since those are an objective evaluation of skills you fail or pass fair and square, rather than an interview where there's always a subjective interpretation of answers given to questions which might not even probe correctly the sought after competences.
On the other hand, I might have failed the English test, which I'd actually prefer.
I wouldn't say this test wasn't objective, don't forget you filled out a personality test and in my experience these tests are rather accurate.
Fact is that there is no real right or wrong in this test, either you're someone who takes the lead or someone who follows, you're someone extravert or introvert, you're very self-confident or rather insecure, etc. For any of these there is no good or bad, but obviously there is a specific type of profile they are looking for. And also obviously this profile will be different than the profile a company is looking for when they want to hire a sales manager, a marketing expert, a scientific researcher, or whatever.
So no idea what the reason is, but there will probably be something that doesn't make you a perfect match for this job, and it's better to find that out now than when it's too late.