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How do I connect a SuccessFund card reader?

As of September 2025, SuccessFund has transitioned from the Zettle card reader to the SumUp card reader. The new SumUp reader includes added functionality and supports swipe payments—helpful for processing gift cards and older credit cards.

You can purchase a SuccessFund-supported card reader at successfund.com/readers.

To connect your SuccessFund card reader, follow these steps:

  1. Download the SuccessFund App
    Install the SuccessFund app on your mobile device.
  2. Log In
    Open the app and log in to view your campaigns.
    • If you’ve never logged into SuccessFund before, you can use a Volunteer Code to log in.
  3. Connect the Card Reader
    The easiest way to connect your reader is by opening a campaign and initiating a payment. The app will automatically begin searching for nearby card readers.
  4. Charge Your Reader
    Ensure your card reader is fully charged and powered on.
    • SumUp: press and hold the power button on the right side.
    • Zettle (legacy): press and hold the top power button.
  5. Choose Your Reader Type
    When signing into the app, you may be asked which reader you have. To change your reader selection later:
    • Open the app
    • Select your campaign
    • Tap More (bottom right)
    • Tap Reset Card Reader Selection
  6. Cancel a Payment (SumUp readers only)
    To cancel a payment in progress, press the power button on the right side of the SumUp card reader.
  7. Update the App
    If you experience issues, make sure you are running the latest version of the SuccessFund mobile app.

ℹ️ Zettle Readers Stop Working in January 2027
Zettle readers will no longer be supported starting in January 2027.


If you are having trouble connecting to the correct reader, uninstalling and reinstalling the app ensures you are running the latest version. If you click on Settings, and Reset Card Reader Selection, you can toggle between Sumup and Zettle readers.

📱 Reader Error Messages

Zettle – “Reader Damaged”

If your Zettle reader shows “Reader Damaged”, this means the device’s internal security system has permanently locked it. These readers are designed with tamper-protection mechanisms that automatically disable the device if they detect shock, impact, temperature extremes, or any sign of tampering. Once triggered, this security lock cannot be undone — even by Zettle or SuccessFund support.

SumUp – “Device Blocked, Please Contact Support”

If your SumUp reader displays “Device Blocked, Please Contact Support”, this also indicates a permanent security lock. SumUp’s card readers contain anti-tampering sensors that disable the device when exposed to extreme conditions (such as being dropped or overheated). This is a built-in fraud prevention feature to protect both you and your customers. Unfortunately, once the reader enters this locked state, it cannot be reset or reused.

What to Do Next

When you see either of these messages —

  • Zettle: “Reader Damaged”
  • SumUp: “Device Blocked, Please Contact Support”

…the device has reached end of life. You’ll need to replace it to continue taking payments.

You can easily order a new reader at successfund.com/readers.

SumUp Connection Error: “We lost connection to the SumUp server”

Connection Error

If you see an orange screen that says “Connection Error” when trying to take a payment, the most common cause is that location services were not allowed when the app was first installed.

The SumUp reader requires location permissions to communicate with the SuccessFund app. If this permission is denied, payments cannot be processed and this error appears.

How to Fix It

Option 1: Enable Location Services in Settings
  1. Open your device Settings
  2. Tap Privacy
  3. Tap Location Services
  4. Make sure Location Services are turned on
  5. Scroll down and select SuccessFund
  6. Change the setting to Allow While Using the App

After making this change, reopen the SuccessFund app and start the payment again.

Option 2: Reinstall the App

If you do not remember what you selected during the initial prompt or the setting doesn’t appear in the list, reinstalling the app will give you a new permission prompt.

  1. Delete the SuccessFund app
  2. Reinstall it from the App Store
  3. When the app asks for permission to access your location, tap Allow