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CP166 notice: what it means and what to do
Got an IRS CP166 notice? Here is what it means, your deadline, what to check before you answer, and how to reply. Check your own letter free: it stays on your phone.
Check my CP166 notice freeWhat the IRS says this notice is about
We couldn’t withdraw your monthly payment because there wasn’t enough money in your bank account.
What you need to do
- If you haven’t already, make a payment .
- Each month, make sure there's enough money in your bank account to cover your monthly Direct Debit Installment Agreement (DDIA) payment by the due date.
Your deadline
Answer by the date printed on your notice. If there is no date, answer as soon as you can, and call the number on the notice if you need more time.
What to check before you answer
Is this letter really from the IRS?
The IRS writes first by mail. A real letter shows a notice or letter number, your name and part of your tax ID number. The IRS does not ask for payment by gift card, crypto or wire transfer. If in doubt, sign in to your IRS online account, where many notices are listed.
Common questions
I sent my monthly payment by mail this month. Why did the IRS still try to withdraw it from my account? (updated March 25, 2026)
Once you establish a DDIA , you’ve agreed to allow the IRS to automatically withdraw your fixed monthly payment on the scheduled date every month. Even if you mailed a payment, we will still try to withdraw it from your account.
I sent my updated checking account information, but the IRS tried to withdraw money from my old account. How can I make sure you have the right account? (updated March 25, 2026)
You can verify and update your DDIA using the Online Payment Agreement (OPA) tool . If your bank charged you a fee because we tried to withdraw from your old account, you’ll need to contact your bank to have the fee waived. Their fees are separate from any IRS charges.
I'm sure I had enough money in my bank account. Why couldn't the payment be withdrawn? (updated March 25, 2026)
You'll have to contact your bank to clarify the situation. In addition, if your installment agreement is now cancelled, you can use the OPA tool to reinstate it.
How can I get the penalty charge for insufficient funds removed? (added March 25, 2026)
If you believe you have a valid reason to remove the penalty, you may qualify for penalty relief .
How do I change my monthly payment date on my DDIA? (updated March 25, 2026)
You can use the OPA tool .
The notice I received said "You may also owe additional interest and penalties." What does that mean? (updated March 25, 2026)
You need to file your return and pay your tax by the due date to avoid interest and penalty charges. If any balance remains unpaid, additional interest and penalties will be added to what you owe.
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