Hey @moeezahmad8
Welcome to the community! Thanks for reaching out for help with your clients welcome series flow.
First, is the signup form still capturing new profiles and adding them to the welcome flows list? If profiles are still being added to the list, is the welcome flow still sending to those new profiles or are they no longer being delivered? Identifying where the customer journey is breaking down is the first step in identifying a solution. When you say the code is not working, do you mean a coupon code? If so, what integration are you using and how are the coupon codes being generated?
There are a number of factors here that we need more information on to be able to find a solution. Please let me know how we can help!