The federal income tax isn't calculating on Form 1040, line 16 in ProSeries

The client has a taxable income amount showing on the Form 1040, line 16 - "Tax" but there's no tax calculated.

How do I resolve this issue?

Make sure that that the following items have been entered:

• Taxpayer's Social Security number
• Taxpayer's date of birth
• Spouse's Social Security number (if Married Filing Jointly)
• Spouse's date of birth (if Married Filing Jointly)
• Filing status

If all of the above information has been entered, check the Tax Smart Worksheet—just before line 16 of Form 1040—to determine which method of tax is computed. View the worksheet to determine how the tax is calculated.

Refer to the IRS instructions for Form 1040 for more information about this form.