If your Tax Return was rejected due to missing IP PIN, it is because the IRS issued an Identity Protection PIN to you. In order to file electronically, you will need this PIN.
You should have received a letter from the IRS with the PIN included. If you didn't receive the letter, you can create an account on the IRS website (if you don't have one) to retrieve it. See the link below:
Get an identity protection PIN (IP PIN)
Then, follow the instructions on the link below to see how to fix the rejection:
How do I fix e-file reject IND-181-01?