When you file for a federal tax extension, approval is “automatic”. As long as your information is submitted accurately by the tax filing deadline, the IRS will approve your extension. The overwhelming majority of tax extension rejections occur when personal information does not match IRS records. In most cases, the IRS rejects extensions because of either an incorrect Social Security number(s) or your last name does not agree with IRS records. You should first check that you have submitted the correct Social Security number for yourself or your spouse.