If you’re experiencing difficulties with connecting your card reader to your smartphone/tablet you have come to the right place. In this article, we’ll guide you through troubleshooting your card reader so you can go back to your sales as fast as possible.

In this article:


Please check first which card reader you’re using. The SumUp Air has “SumUp” written on the back of it. The PIN+ has “PIN+” written on the back.

Connect your Card Reader manually

Normally your card reader connects to your smartphone/tablet on its own. But fret not, here’s a quick guide on how to do it yourself:

  1. Open the SumUp App and log in with the email and password you registered with.

  2. Tap on the “Account” tab (iOS) or menu symbol (Android) in the top left corner.

  3. Please open “Payment methods”/ “Choose your card reader” and choose whichever card reader you own to start with the set up.


    The following two steps are only necessary for SumUp Air Card Readers with a serial number lower than 100017050828.

  4. If you own a SumUp Air, please confirm the pairing request on your smartphone/tablet by comparing the last 3 digits that are shown on your screen with the last 3 digits of your card reader’s serial number. Tap “Connect”.

  5. Connection successful! Your card reader is now preparing for its first transaction. This process takes about 2 minutes.

General troubleshooting

You still can’t connect your card reader? Don’t worry, we’ve got your back. Here are some things that might fix your issues.

Please check this article first to see, if your device is compatible with the SumUp Air Card Reader.

Update the SumUp App

Please check if you have the latest SumUp App version.

For iOS users
  1. Go to the App Store.
  2. Click on “Updates” in the bottom right corner.
  3. If you can find the SumUp App on the list, click the “Update” button right next to it. If you can’t find the SumUp App on the list your app is already up to date.
  4. Please try to take a card payment again to see if your card reader connects to your device.

For Android users

Restart smartphone/tablet

Please restart your smartphone/tablet. By doing so the Bluetooth chip in your device will automatically restart which can fix the connectivity issue you are experiencing.

Reinstalling the SumUp App

If updating the app didn’t help you might need to delete the SumUp App and reinstall it.

For iOS users
  1. On your home screen push down lightly on the SumUp App icon until it starts to dance and an “X” appears in the left upper corner of the app.
  2. Now click on the “X” and confirm the deletion process by clicking “Delete”.
  3. Go to the App Store and type in click on “Search” in the menu bar on the bottom.
  4. Type in “SumUp” in the search bar and tap “Search”.
  5. Your device should find the SumUp App as the first entry. Click on the “Get” button next to the icon and your iPhone/iPad will download the SumUp App.
  6. Now open the SumUp App as usual and log in with your email and password.
  7. Please try to take a card payment again to see if your card reader connects to your device.
For Android users

Troubleshooting Air Card Reader

Battery level

A low battery level can cause connectivity issues which is why we recommend charging your card reader. You can charge the SumUp Air Card Reader with the Micro USB cable included in the package. Just plug it into a power supply or a computer.

The battery level is shown on the display of the card reader as well as through the blue LEDs at the bottom of the reader. To view the battery level, press the power button and quickly release it again. Depending on your card reader’s battery level the LEDs will light up. One LED equals about 25%.

Restart Card Air Reader

If none of the above solved your connectivity issue you can also restart your reader. This option should only be used sparsely. Hold down the power button of your card reader for about 10 seconds and release. This way the Bluetooth chip in your card reader restarts.


Never restart your SumUp Air Card Reader while charging as this can damage your card reader.

Troubleshooting PIN+ Card Terminal

Please check this article first to see, if your device is compatible with the SumUp PIN+ Card Terminal.

Restart PIN+

You can restart your card reader along with its Bluetooth chip by opening and closing the battery compartment. This can fix connectivity issues.

Replace batteries

A low battery level can cause connectivity issues which is why we recommend switching out the batteries of your card reader. Please only use AAA 1.5 V batteries (no rechargeable batteries). Incorrectly inserted or empty batteries can cause transactions to fail, even if the device turns on. Always check the proper alignment when putting in new batteries by familiarising yourself with the +/- symbols on the device (see picture below).



Activate Bluetooth Mode

Since you can connect the PIN+ to your smartphone/tablet via Bluetooth as well as cable you have the option to switch between those two modes. To ensure that Bluetooth mode is active, please follow the steps below:

  1. Hold down the power button for 10 seconds.

  2. Two symbols, one for cable (left) one for Bluetooth (right), will appear on your card terminal’s screen. A square indicates which mode is activated.

  3. If the square moves from cable mode to Bluetooth mode, it means that Bluetooth mode is now activated.

  4. If you accidentally selected cable mode, just hold down the button again for 10 seconds and the square will switch back to Bluetooth mode.

Blocked device

Your Card Reader is secured from manipulation by technical safety mechanisms. Please handle your Card Reader with care. Avoid external force or hard impact (for example falling on the ground) to not trigger the mechanism. Once it is triggered, the device will be permanently disabled and can no longer be used.

Should this happen the message “INVALID BPK” (Air) or “Device Blocked” (PIN+) will appear on your card reader’s screen. In this case, your device needs to be replaced. Please contact our support (UK: support@sumup.co.uk, IE: support@sumup.ie).

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