In the past year we have been emailing to our lists on Constant Contact using its browser-based tool to build and schedule the emails. Generally very good deliverability
In the last few weeks we've started using the Constant Contact API to automate email generation at our server and created/schedule emails with Constant Contact via their API.
Now all of a sudden we are getting reports that SOME list recipients are "not getting" their daily email from us, and those emails are ending up in their spam filters.
I know, because I'm on the list, and suddenly my daily email from the list is ending up in spam too.
I can "approve" the "sender" of the email in my spam filter, but every day that "sender" changes, thus triggering another email caught in spam.
My spam filter is looking at the Return-Path in email head to determine sender, like:
...and that Return-Path changes every day, with every email sent to list. And so now spam filters are picking up on that.
But oddly, when the emails were SUCCESSFULLY posted to list (before we automated using the CC API), the Return-Path was set in precisely the same way, from all I can tell looking at older emails sent to list.
So I'm stumped. I am correctly setting the from_email and reply_to_email vars in the API call, using an approved email address to set both. What am I missing?
When you are creating custom code emails of your own through the API, it is important to note that Constant Contact simply takes the code that is given and creates a custom code email as though it was created in the UI. Unfortunately, this means that the filtering will not have anything to do with the email specifically being created through custom code.
It is very likely that the filtering may be a result of a content filter being tripped or potentially a specific filter that is marking emails received from some Constant Contact servers.
What I would strongly suggest is to call our support team at (866)-289-2101 and have some information for them such as mail provider name and/or spam filter program name that they can look into in order to see if it can be resolved through content or if there are any outstanding issues.
API Support Specialist