Why won't the gates open when I touch my card on the reader OR why does the gate show a red light when I touch my card on the gate?

There are four main reasons why the gate may not open when you use your card:

You may have used two or more contactless cards (such as your contactless card, an Oyster card or building pass) on the reader at the same time. To prevent this, only touch one card on the reader to avoid paying with a card you don't intend to use.
Your Transport for London (TfL) account may have been disabled if you have an unpaid TfL fare. You can resolve this through your online TfL account or by phoning TfL Customer Services on 0343 222 1234*. Please be aware that it may take up to 30 minutes before you can use your card to travel again, however this won't affect your ability to use your card at other retailers. You can also use an alternative payment method until the issue is resolved.
Your account may not be in order (for example you're over your limit). If this is the case you'll need to contact us first to resolve the issue. Once resolved you'll need to contact TfL who will approve your card for future travel. Please be aware that it may take up to 30 minutes before you can use your card to travel again.
Your card may not be contactless enabled. Please look for the contactless symbol on your card. If you have Barclays debit card queries you can either visit us in a branch or call us on one of the numbers below:

For Barclaycard queries please call us on 0333 200 9090. Call charges may apply. We also offer a Next Generation Text or SignVideo service. For more information visit barclaycard.co.uk/accessibility

*Call charges apply, please visit tfl.gov.uk/callcharges for details.