Password of ITR pdf file - acknowledgment receipt ?

I just got ITR V acknowledgment receipt. My lawyer who looks upon my tax payment gave me print and also gave me pdf file which I asked. But this pdf file is asking for password. I provided my pan number but it is not working, I provided my date of birth as in pan card but still not working, please tell me what is the password this file. It is driving me nuts..

It is very simple, it is your pan number followed by date of birth on pan card.
Example:
Say your PAN number is KNUP23161F and date of birth is 21-July-2001 then password would be :
KNUP23161F21072001

Cheers..