I have been working on my abandoned cart flow, and for the final email, I want to give the customer a coupon code for 20% off their order. I have changed the URL on the button to: https://www.scamperandco.com/52837908680/checkouts/{{ event.extra.token }}?discount={% coupon_code 'ABANDONCART20' %}, but that leads to the following error:
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Any idea what I am doing wrong?