Rejecting a candidate after giving an appointment letter

Generic answer seems to be: Yes!

It is an offer letter or appointment letter?

You are from which side; employee or employer?

Post full facts of the matter.

Iam an employee and I got an appointment letter from the company that so and so is the date of joining wen I went on the date they had done certificates verification and they rejected me

What is the fault found in our certificates?

Have the employer stated the reason for not allowing you to join, in writing?

Were you asked to show certificates during interview also?

Were you working previously and asked to resign (in writing say by offer letter) before joining this company?