App Card Rejection - robots.txt charset at fault?


We’ve been attempting to get our App Card approved, and while the tags on our domain look correct in the validator, we keep getting rejected, with a rather unhelpful email that fails to go into detail on why.

We’ve ensured that we have all of the required tags, and our robots.txt file does not block TwitterBot. The only thing we can find is that our robots.txt file is being served with the UTF-8 chareset, rather than the documentation specified encoding of us-ascii. We are unable to change this encoding however - has anyone seen a similar issue?