Only works with accounts that haven't made an order before. Have tried it with a new account and it works.
T&C's:
Maximum discount value of $20. Other fees (including service fees), taxes, and gratuity still apply. May only be used by new customers to Doordash on their first 2 orders. All deliveries subject to availability. Must have created a valid DoorDash account with a valid form of accepted payment on file. Qualifying orders containing alcohol will be charged a $0.01 delivery fee. No cash value. Non-transferable. Enter AU50OFF2 at checkout for each redemption.
Better to use a referral code - I user one that gave me $15 off min $20 spend for the first 3 orders, also first 3 free delivery