I’m using Heroku to deploy my Play! framework app. I have a form that

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Asked: May 29, 20262026-05-29T15:56:28+00:00 2026-05-29T15:56:28+00:00

I’m using Heroku to deploy my Play! framework app. I have a form that

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I’m using Heroku to deploy my Play! framework app. I have a form that uses the standard structure of

public static void showForm() {
    render();
}

public static void handleForm(@Required param, @Required otherParam, etc) {
    if (validation.hasErrors()) {
        validation.keep();
        showForm();
    } else {
        //process form parameters
    }
}

This works fine on:

dev machine running HTTP at localhost:9000
heroku running HTTP at www.myapp.com
dev machine running HTTPS at localhost:9443

However, for forms that do this on Heroku over HTTPS at secure.myapp.com using hostname-based SSL, the validations don’t show up. I think the problem is that validation.keep() isn’t working.

If validation.keep() makes a cookie, and the problem has something to do with the difference between www.myapp.com and secure.myapp.com, then I might have a deeper problem because:

I already have application.defaultCookieDomain=.myapp.com, as per this question.
I think that both the GET and the POST are happening over HTTPS, so I think they have the same domain anyway…
- The form’s GET is definitely over HTTPS
- When the form’s data is processed, its result is definitely shown over HTTPS
- I guess it’s possible that the POST is happening over HTTP (and thus www.* instead of secure.*, but I’m not sure how to check).

Anybody have any guesses as to what’s going wrong?