Hii

You must reupload the signature once again and make sure that the signature you upload is not in capital font, is very clear and visible. Has no spots of ink anywhere, in written clear enough in running hand. Has no initials rater full spelling of the name. Has a white background and is either in blue or black ink only. Prefer black ink itself. Also ensure while you scan the signature, it must not be blur.
If you problem still persists, then i would suggest you to mail your query on the following email id - neetug-nta@nic.in
Also try the helpline numbers - 8076535482 , 7703859909

Hope this helps
Thanks!!