Tracing source of web app call

[#1]

Hello--

Just wondering if anyone here has ideas on how to trace a web app call to determine source. I have a web app that takes in name, email address and service ID to add that new recipient to a service (an email newsletter subscription, in this case). We have removed the one web page that we know that's been using this web app (essentially a web form that's using an HTTP POST command), but for some reason, I keep seeing new signups every day. Our marketing team is not aware of any active acquisition channel for this newsletter at this time, so this is very bizarre.

Is there any way to figure out where these new signups are coming from?

Thanks in advance for any insights. I have a ticket open with Customer Care, but just wondering if anyone here had come across this situation before.

Sonny

[#2]

Hello Jean-Serge--

Thank you for your reply. You're right; web tracking in the web app properties will not help in this case. Yes, we have GA but the problem is that I don't know which web page is using the web app. We have shut down this newsletter service and basically deleted the web page where we used to collect subscribers (and we have stopped sending emails to them since early August), which is why it's puzzling that we're still getting new signups. I am assuming that this source is some rogue legacy page (or worse, some sort of a script) that has predated all of us on the team and so no one knows about it (which is terrible, I know, but oh well). As an aside, every single one of these new subscribers has a hard-coded zip code of 55401 (Minneapolis, MN -- where we don't have a market presence; the newsletter was local to Oregon residents!)

And yes, every web app that I created after I started on this job has that origin parameter in the query string for attribution, reporting and analysis purposes.

Which leaves us with the logging. I like this idea. We are not on-prem, but I suppose I can ask Adobe Support to enable verbose logging for at least a day?

Thanks again,

Sonny