Bittrex rejected my enhanced verification for a weird reason

[joypark333]

I did what Bittrex told me to do. Upload a selfie and an image of my passport. All of my personal information is on the image. To my surprise, I still failed the verification. I asked the Bittrex support and here is the reply.
https://imgur.com/pyNkB6A
What signature? I don't understand. I checked the image that I uploaded, there is no problem with it.
Does anybody have the same issue? Could you tell me what does this mean? Thanks!

[Pab]

simple i think no your signature on your passport