firstly make sure you have filled correct roll number or date of birth format  even if you did it correct sometime it is mistake from their side don't worry just leave a email or contact them on official number here is contact details  1   neetug-nta@nic.in   2 cbseneet.nic.in. 3 ntanationaltestingagency@gmail.com 4-7703859909,8076535482