We're implementing Triggered Send functionality for real time email roll out in MC. We have also written AMPScript in email templates to fetch values from a custom object. As Triggered Send can work only with Contact and Lead objects, we're using AMPScript to dynamically fetch values from custom object records.
We have a DE (Data Extension) used to store records with Subscriber relationship as Subscriber Key relates to Subscribers on Subscriber Key.
While we are doing this, we're facing a issue during email send. While testing using "Generate Preview" button, "Subscriber Key" is getting changed to "Email Address" and MC throwing error. We've no idea why MC is changing subscriber id as email id.
Can someone help me out here, as this is a critical requirement am working on.