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# Block checkout by email, phone, name, address or customer tag

## Overview

Stop a known fraudster from ordering again, using the details they type at checkout. **Block checkout fields** rules look at what the shopper enters in the checkout form. When the email, phone number, name, country, address, zip code or customer tag matches a rule, Shopify stops the checkout and shows your error message instead of creating the order. You set up these rules in **Block Checkout > Block checkout fields**, and each rule has its own error message that you can preview before saving.

## What you'll learn

* [Requirement](#2-requirement)
* [How to create a Block checkout fields rule?](#2-how-to-create-a-block-checkout-fields-rule)
* [Customize the error message](#2-customize-the-error-message)
* [How it works?](#2-how-it-works)
* [Who can use this feature?](#2-who-can-use-this-feature)

## Requirement

| The **Block Checkout by Blockify** rule must be on in **Settings > Checkout > Checkout rules**. See [A complete guide: Block Checkout](https://help.omegatheme.com/en/article/a-complete-guide-block-checkout-16e3g50/).

## How to create a Block checkout fields rule?

### Step 1: Open the rule form

Go to **Block Checkout > Block checkout fields** and click **Create rule**.

![](https://storage.crisp.chat/users/helpdesk/website/-/8/3/8/3/8383e5404a31c000/20250910-100918_1c7lqgk.png)

### Step 2: Set the rule status

Choose **Enable** to apply the rule as soon as it is saved, or **Disable** to save it switched off.

![](https://storage.crisp.chat/users/helpdesk/website/-/8/3/8/3/8383e5404a31c000/image_1qjqgcq.png)

### Step 3: Choose the condition

Under **Select condition** pick one of **Email**, **Phone number**, **Name**, **Country**, **Address**, **Zip code**, **Customer tag**.

![](https://storage.crisp.chat/users/helpdesk/website/-/8/3/8/3/8383e5404a31c000/image_iyccw2.png)

### Step 4: Enter the values

Type the values to block (formats below). Where an **Operator** selector is shown, **contains any of** blocks checkouts matching any value; **does not contain any of** blocks everything except those values.

![](https://storage.crisp.chat/users/helpdesk/website/-/8/3/8/3/8383e5404a31c000/image_fv63u6.png)

#### Upload a list of addresses

For a new **Address** rule, **Select type** offers **Manual** (type the address) or **Upload CSV**. With **Upload CSV**, drop your file (a spreadsheet saved as a .csv file) into the upload box; each row becomes a blocked address. The line under the box, "Download **the sample file** for format", links to a sample with the expected layout.

| Important: CSV files can be up to 2 MB and 2,000 lines of addresses. If some rows are in the wrong format, the error under the box links to a file that lists them; the error also names any address already used in another rule.

![](https://storage.crisp.chat/users/helpdesk/website/-/8/3/8/3/8383e5404a31c000/block-checkout-by-customer-det_1ai6q9v.png)

You can't change the type after you save the rule. Other conditions only accept values you type in.

### Step 5: Set the error message and save

Under the **THEN** block, keep the default message or pick a preset — see [Customize the error message](#2-customize-the-error-message). Add a private **Note** if you want, then click **Save**.

![](https://storage.crisp.chat/users/helpdesk/website/-/8/3/8/3/8383e5404a31c000/image_ko2747.png)

## Customize the error message

Every **Block checkout fields** rule has its own error message: a generic "Service temporarily unavailable" that gives nothing away, a branded note with your store name, or your own wording. You set it under the **THEN** block of the rule and check it in the **Preview** panel before saving.

### Quick preset or Write custom

Open the rule (**Create rule** or an existing rule) and scroll to the **THEN** block. Under **Quick preset** choose a ready-made message from the **Generic** or **Branded** group, or select **Write custom** and type your text in **Message text** (single line, up to 255 characters).

| Group | Preset | Message shown |
| ---- |
| Generic | **Service unavailable** | Service temporarily unavailable. Please try again later. |
| Generic | **Error occurred** | An error occurred. Please try again. |
| Generic | **Cannot process** | Unable to process your request at this time. |
| Generic | **Try again later** | Something went wrong. Please try again later. |
| Generic | **Order blocked** | Your order cannot be completed at this time. |
| Branded | **Branded — unavailable** | {shop_name} is currently unavailable. Please contact support. |
| Branded | **Branded — contact support** | Please contact {shop_name} support for assistance. |

{shop_name} is replaced with your store name. **Write custom** replaces the preset with your own text. Rules without a custom message use the default "Order cannot be placed due to suspected fraud."

### Position, Icon and fake error code

* **Position** — choose **Top of the checkout page**, **Bottom of the checkout page** (near the pay button) or **Inline near the triggering field** (next to the field whose value matched the rule).
* **Icon** — turn on to show a warning icon next to the message.
* **Append fake error code** — turn on to add an error code after the message.

### Preview and save

The **Preview** panel on the right shows the message in Shopify's default checkout style. When it looks right, click **Save**. Different rules can have different messages.

![](https://storage.crisp.chat/users/helpdesk/website/-/8/3/8/3/8383e5404a31c000/image_17g6ojd.png)

![](https://storage.crisp.chat/users/helpdesk/website/-/8/3/8/3/8383e5404a31c000/customize-the-checkout-error-m_18yh9q7.png)

| Tip: a generic preset with **Append fake error code** on looks like an ordinary store error, so fraudsters can't tell which detail to change. Use a branded preset when you would rather have a real customer contact you.

## How it works?

Every rule reads as **Rule summary » IF** condition **» THEN Block checkout · Show custom error**, with an **Active** or **Inactive** badge. Conditions differ only in the value:

| Condition | Value format | Example |
| ---- |
| **Email** | Full addresses or words contained in the address, comma-separated | test@gmail.com,test1@gmail.com — or abc,test |
| **Phone number** | Numbers, comma-separated | 012345678,0987654321 |
| **Name** | First name, or **Firstname Lastname**, comma-separated | John Smith,Michael Brown |
| **Country** | One country from the list | Nigeria |
| **Address** | An address line, or a CSV file of addresses | 123 Main St, New York |
| **Zip code** | Zip codes, comma-separated | 10020,00120 |
| **Customer tag** | Type a tag and select it; several tags match any of them | wholesale, blocked |

| **Customer tag** only applies to shoppers already in your Shopify customer list; a first-time visitor has no tag to match. You can't add a value that is already in another rule.

Once the rule is saved, Blockify stops any matching checkout and the shopper sees the rule's error message, by default "Order cannot be placed due to suspected fraud."

![](https://storage.crisp.chat/users/helpdesk/website/8383e5404a31c000/image_s9aggi.png)

The rule list shows each rule with its note and **Created time**. Use **Searching by email, phone number, name, country, address** to find a rule, then turn it on or off, edit it or delete it from the row.

![](https://storage.crisp.chat/users/helpdesk/website/-/8/3/8/3/8383e5404a31c000/imgv302vs64ee3e92-b1eb-458b-b2_auf798.png)

## Who can use this feature?

Available on the **Enterprise** plan and above. On lower plans the **THEN** block shows **Upgrade to Enterprise to customize error messages**.

## FAQs

1. **Can one rule hold many values?**
Yes. Email, Phone number, Name and Zip code accept comma-separated lists, and a new Address rule accepts a CSV file of up to 2,000 addresses.

2. **Does blocking an email cancel that customer's existing orders?**
No. The rule only stops new checkouts. Existing orders are handled in **Fraud Filters**.

3. **Why was a tagged customer not blocked?**
They checked out as a guest or with an email not yet in your customer list.

4. **Can the error message use more than one line or formatting?**
No. The message is a single line of plain text, shown in Shopify's default checkout style.

5. **Does the custom message apply to Quick Setup protections too?**
No. Quick Setup protections use the **Error message** field under **Quick Setup** on the Block Checkout page.

6. **What does the shopper see if two rules match?**
A single message. The shopper is blocked once, not once per rule.