A small percentage of our customer are reporting that they are not receiving some of the NPS Survey emails - checking the JO Analytics, there are no bounces being reported.

Is there any further data available within the platform that can help verify this is correct?  

We’re routing the comms through our mail server so I’d be surprised if they’re being  blocked.  The only thing I can think of, is the link inside the email is causing problems? 

Any ideas welcome!