The "CP 54" series of notices is issued to alert the taxpayer that:
there is a problem with name and identifying number on the tax return or the estimates paid, or
the IRS is holding a refund for a prior year because the name and Social Security Number (SSN) or IRS Individual Taxpayer Identification Number (ITIN) on the recipient's tax return didn't match information in IRS records or records provided by the Social Security Administration.
This notice is now only applicable to paper-filed returns, as the IRS has Name and Identification number verification in place for electronically-filed returns.
Contact the Social Security Administration (SSA) to update your records if you have an SSN and any of the following occurred:
you recently married and are using your spouse’s last name and you did not contact SSA to update your records,
you legally changed your name without contacting SSA to update your records, or
your social security number and/or name are different from when you received your social security number.
Contact the IRS, ITIN Operation, to update your records if you have an ITIN and any of the following occurred:
you recently married and are using your spouse’s last name and you did not contact IRS to update your records,
you legally changed your name without contacting IRS to update your records, or
your ITIN and/or name are different from when you received your CP565, ITIN Assignment Letter.