Most card reader connection problems are fixed by updating everything, checking Vintner's permissions, restarting the reader and pairing the reader again from inside Vintner. Try these checks in order.
Checks for every card reader
Update your iPad or iPhone. Vintner needs iOS 26 or later on iPhone, or iPadOS 26 or later on iPad. Open the Settings app, tap General > Software Update, and install any update. If your device can't update to version 26, it's too old to use with Vintner.
Update the Vintner app. Open the App Store, tap your profile picture, and update Vintner if an update is listed.
Pair each iPad with only one card reader. On the iPad or iPhone, open Settings > Bluetooth and look under My Devices. Only one card reader should be listed. If an iPad is paired with more than one reader, Vintner bounces between the readers, which causes dropouts. For any extra reader, tap the i next to it, then tap Forget This Device.
Pair each card reader with only one iPad. A reader that's paired with more than one iPad can drop its connection when another iPad connects to it. Keep one reader with one iPad, and label them so staff keep them together.
Check Vintner's permissions. Open the Settings app, scroll down and tap Vintner. Check that Location is set to While Using the App, Bluetooth is on, and Local Network is on. Vintner needs all three to find and connect to card readers.
Restart the card reader. Turn the reader off, wait 10 seconds, then turn it back on.
Restart the Vintner app. Close Vintner completely, then open it again.
Pair the reader from inside Vintner. Always connect the reader from inside the Vintner app, not from the Settings app on your iPad or iPhone.
Charge the reader. A reader with a low battery can drop its connection or refuse to update.
Check your internet connection. Open a website on the iPad or iPhone to check it's online.
Checks for your type of reader
BBPOS WisePad 3 or Stripe Reader M2 (Bluetooth readers): see What to try if your BBPOS WisePad 3 won't connect.
BBPOS WisePOS E, Stripe Reader S700 or Stripe Reader S710 (smart readers): see What to try if your WisePOS E, S700 or S710 won't connect.
Tap to Pay on iPhone: see What to try if Tap to Pay on iPhone isn't working.
If the card reader still won't connect
Contact WithWine support. Tell us which reader you're using, its serial number (on the back or under the reader), the iPad or iPhone model, and what you've already tried.