I can confirm that it says "not found" and "not active" for your account.  That does seem a little strange.  The only think I can guess is that it might be related to your feedback/trust.  I have removed default trust from my trust list so I see your trust rating as 0.  But I noticed that you do have quite a few negative feedbacks.  I don't know if some of those feedbacks are on default trust and bitmixer.io has finally implemented a trust filter for default trust or if they've got some other algorithm which disqualifies people with too many negatives.  Note that this is speculation.  I'm merely confirming that it seems like although you have the signature in place at the time of this writing the signature page does indeed say "not active" and "signature not found".

Good luck!