How old are you?
There's a difference between taxes and penalties. If you are over age 59-1/2, or were over age 55 when you separated from the employer, you don't pay an additional penalty. But you always pay the income taxes.
The withholding is an estimate, your actual tax might be more or less, and is only calculated on your tax return after combining all your income, deductions and credits. If the 30% withholding covered your tax in previous years but does not cover your tax this year, maybe you have other income this year.
