Hello @toastytoad,

Thanks for sharing your question with the Klaviyo Community!

Since it sounds like the Back in Stock event is being triggered correctly, this sounds like something pertaining to the flow itself. I’ve listed some common issues below that may cause a flow to not be sending out with some resources pertaining to each points below:

• Ensuring flow emails are Live prior to subscribing to the back in stock product and switching the product from out of stock to in stock
  • How to Enable a Flow to Start Sending
• Seeing if your have any flow filters in place that may be causing your test profile to be excluded or skipped from the flow
  • ​​​​​​​About Flow Triggers and Filters
• Making sure you have restocked your product with more than what your Back in Stock’s notification inventory rule is set for
  • Minimum Inventory Rules
• Checking to see if you have other settings that may be prevent the users from receiving the flow such as Smart Sending
  • ​​​​​​​Guide to Smart Sending in Klaviyo
• Is the profile you are testing with a suppressed profile?
  • ​​​​​​​About Suppressed Profiles in Klaviyo

From most of these common issues, such as if you had flow filters in place, your profiles were skipped due to smart sending, or the profile you tested with was suppressed, you can check this within the flow email’s Analytics tabs under Recipient Activity. Within this section, you can see a variety of data such as how many profiles received the email, clicked on the email, or were skipped from the email. 

Klaviyo also offers a Troubleshooting a Flow interactive guide that can further help you determine what the likely cause of your flow not sending out may be.

I hope this helps!

David