Why that

"Your Account Cannot Be Automatically Enabled At This Time"
I only hold a small amount there << 1000 $ and I'm located in the EU.
What is going on there ? The next Mt Gox

According to the Bittrex terms, For accounts valued at over $1k they require additional info as proof of identity. Bittrex is upping their security this is good for the most of people. Just follow the instructions and you'll be fine.