Hi @takahashi,

Thank you for sharing this question with us.

First, make sure that the coupon code you are trying to use in your Campaign email does not have a variable expiration date. A coupon with a variable expiration date will use radio button: “Expiration after a certain number of days/hours”. We recommend using “Expiration: On a certain date” instead for campaign sends. For more information. I recommend reviewing our documentation on Using Your Coupon in an Email Campaign.

Additionally, please also make sure you have added a sufficient amount of codes prior to scheduling your Campaign. You can generate coupon codes for a particular coupon by clicking the dropdown menu and selecting Add Codes. Once you select Add Codes, you will be prompted to input the number of codes you would like to generate. You’ll need to make sure to generate at least as many codes as you have expected recipients for your campaign, otherwise, you will not be able to send or schedule it.

I hope that is helpful! Let us know how it goes.