To try to reduce or eliminate it, review the TurboTax article Why am I getting an underpayment penalty?
For more information, refer to the TurboTax help article Guide to IRS Tax Penalties: How to Avoid or Reduce Them for tips to use in the future.
You can contact the IRS to request a one-time abatement of your underpayment penalty. For individual tax returns, call 1-800-829-1040, 7 AM - 7 PM Monday through Friday local time.