# Blocked ACH Direct Debit payments

Stripe uses information collected across our services to detect and block risky transactions to help protect merchants from fraudulent transactions, elevated chargeback rates, and dispute fees. Blocked bank payments may occur due to blocked bank accounts. This article explains why bank accounts are blocked and how to investigate and resolve blocks.
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### How do I determine why a payment was blocked?
The steps required to unblock a customer’s bank account depends on the reason it was blocked.
To find the block reason associated with a specific payment:
* Open the [Stripe Dashboard Transactions page](https://dashboard.stripe.com/payments?status%5B0%5D=blocked) and locate the payment’s `payment_intent.payment_failed` event with the status `blocked`.
* Locate the `last_payment_error` of the event and identify its `code` field. `code` indicates why the payment was blocked.
  * Payment intent failures may have failed due to a [Radar rule block](https://docs.stripe.com/radar/rules). Find the `outcome` block and view the `reason` to determine why it was blocked.
* Look up the `code` reason in the [handling blocked bank accounts table](https://docs.stripe.com/payments/ach-direct-debit/blocked-bank-accounts#block-category-table) for next steps on how to unblock the bank account.
### Why are bank accounts blocked when ACH Direct Debit payments are blocked?
When an ACH Debit is returned due to reasons other than insufficient funds, NACHA rules require Stripe block certain bank accounts. Stripe maintains the block until the root reason is addressed to reduce fraud and avoid repeated dispute and return fees.
An ACH Direct Debit payment may be blocked for many reasons, including:
* Bank-initiated failures, such as closed or frozen accounts.
* Customer-initiated disputes, such as disputing an unauthorized payment.
* [Stripe Radar](https://docs.stripe.com/radar) determines the payment is high-risk.
Stripe doesn’t block bank accounts because of past insufficient funds returns.
### How does Stripe Radar help protect your ACH transactions?
See How Radar prevents ACH and SEPA Direct Debit payment fraud.
### How can I prevent blocks?
* Confirm customer bank account ownership and details with [Financial Connections Instant Verification](https://stripe.com/financial-connections).
* Use clear statement descriptors for your business name to help customers recognize your payments and avoid accidental disputes.
* Have your customer provide Stripe Company IDs to their bank to enable Debits initiated by Stripe. Some banks automatically reject ACH Debits attempts from unknown entities.