We have the situation, that we are sending Triggered Emails via REST Api. All subscribers are stored in Triggered Send Data Extension. The Email is the primary key.
In case a user enters an already existing Email the Triggered Email will not be triggered, because the email already exists in the Data Extension. That is correct and expected.
The thing is, in this case the response would still look like this:
"responses": [
{
"recipientSendId": "some ID numbers",
"hasErrors": false,
"messages": [
"Queued"
]
}
]
So I find no way to make it possible to give the user an error message on the website saying something like "you email is already in use".
Are there any ideas how to handle that? I guess this case might occur frequently.