Form Plugin Error

When sending an email through the Form plugin, an exception is called by Twig. The error is as follows:

Whoops\Exception\ErrorException thrown with message "Call to a member function header() on a non-object"

#0  in C:\Bitnami\wampstack-5.5.28-0\apps\grav\htdocs\user\plugins\login\logi n.php:112

This happens when I submit the following through the form generated by the Form plugin (with the Email plugin enabled, running sendmail through localhost SMTP). The form page looks as follows:

title: A page with a form
    name: contactform
        - name: name
          label: Name
          placeholder: Enter your name
          autofocus: on
          autocomplete: on
          type: text
            required: true

        - name: email
          label: Email
          placeholder: Enter your email address
          type: text
            rule: email
            required: true

        - name: message
          label: Message
          placeholder: Enter your message
          type: textarea
            required: true

        - type: submit
          value: Submit
        - type: reset
          value: Reset

        - email:
            subject: "[Grav Contact] {{|e }}"
            body: "{% include 'forms/data.html.twig' %}"
        - save:
            fileprefix: contact-
            dateformat: d-m-Y-H-i-s-u
            extension: txt
            body: "{% include 'forms/data.txt.twig' %}"
        - message: Thank you for getting in touch!
        - display: thankyou

And I sent the following to test: “Name: Jesus Christ, Email:, Message: A page with another form.” That is, the mail is clearly sent as it is caught by the Fake SMTP Server, but the page redirects to the error when submitting.

Any thoughts on why this occurs, and how to fix it?

DId you create a thankyou subpage as explained in

(you set the form to display a thankyou page. If that is missing, you get that error)

You are correct, I forgot to create it after I moved the templates over. With it in place the error doesn’t appear. Hopefully Grav will at some point resolve those errors with a bit more hinting to what I messed up.

Thanks for the help!

Good suggestion, I added a more meaningful error