The IRS or the Social Security Administration usually issue a number called the Taxpayer’s Identification Number which is used for administration of tax laws. IRS reference code 9001 means that the taxpayer has tried to access the refund status using a secondary tax identification number which is not the right way of checking it. Hence the refund status is not returned. Taxpayers will need to get a primary tax identification number by applying to the SSN, EIN or ITIN which would then be used for all subsequent queries. The proper procedure is also highlighted in the IRM or internal revenue manual.