In most cases, it's super simple to connect your card to your Uber account. Head to the Uber app and you'll see a section named 'Payment' in the side panel, where you can add a new payment method and enter your card details.
We've noticed that Uber is set up a little differently to how we'd expect because they seem to have more than one 'merchant identity' for their UK market.
At least one of the Uber merchants doesn't accept the Coconut card - our guess here is that it's an older one. As a result, you might have trouble paying your fare with your card if that's where you've been allocated by Uber.
There's a fairly straightforward way around this if you have a PayPal account. Simply connect your Coconut account (rather than card) to PayPal and select this as your payment method for your business/work related journeys.