Alert Me! Restock Alerts

I added this app so customers could let me know when they wanted to be notified when an item was back in stock. The process was easy & what I couldn't figure out, I emailed support & they helped me right away!

as of 9/14/2020, I am no longer able to see the "restock" selection on my site. emailed support twice to get help. have not heard anything back yet. I got an error message on my site "Liquid Error" which never happened before 9/11/20. hoping to get this resolved soon. or I will have to find another app