I have attached a link below. It includes valid certificate format for OBC & NCL candidates.

https://jointseatallocationauthority.in/wp-content/uploads/2015/07/OBC-NCL-Certificate-Format.pdf

Make sure that your obc certificate should be in this format only. Also check whether your certificate is issued by the competent authorities or not.

The authorities competent to issue Caste Certificates are indicated below:

(i) District Magistrate / Additional Magistrate / Collector / Deputy Commissioner / Additional Deputy Commissioner / Deputy Collector / Ist Class Stipendiary Magistrate / Sub-Divisional magistrate / Taluka Magistrate / Executive Magistrate / Extra Assistant Commissioner (not below the rank of Ist Class Stipendiary Magistrate).

(ii) Chief Presidency Magistrate / Additional Chief Presidency Magistrate / Presidency Magistrate.

(iii) Revenue Officer not below the rank of Tehsildar’

(iv) Sub-Divisional Officer of the area where the candidate and/or his family resides.