Why is my first order discount code not working for new subscribers?

Topic summary

A Shopify merchant set up an automatic discount code called “First Order” targeting customers who are both first-time buyers and email subscribers. However, customers attempting to use this discount code are receiving an error message stating “This code is not available for you right now.” The discount was functioning properly initially but has since stopped working. The merchant is seeking help to diagnose why the previously functional first-order discount is now failing for eligible customers in their targeted segment.

Summarized with AI on November 21. AI used: claude-sonnet-4-5-20250929.

I have created an automatic discount - First Order which is directed to customer segment who are ordering for the first time and have subscribed. When they are trying to place a discount by entering the discount code they are getting a prompt that - This code is not available for you right now. It was working earlier and now its not working. Please look in to this asap.