File submission in form not working - Statamic 3

Hey,

I've created a form for visitors that contains some text fields and a file upload field. But I cant's seem to get the file upload to work. I feel like I've done what's written in the docs.

When I submit the form it looks like it goes through, but the file isn't saved anywhere... Then when I go to the forms section in the control panel I can see my submission with all of the right data/texts except that the asset field is empty.

So if someone has an idea to why it might not work that'd be very helpful!

This is from my template: resources > views > sets > career.antlers.html

 <div class="career_form">
                {{ form:career files="true" }}
                    {{ if success }}
                        <div class="success_message">
                            Form was submitted successfully.
                        </div>
                    {{ /if }}
                    {{ fields }}
                        <div class="career_form_item">
                            {{ if error }}
                                <p class="error_message">{{ error }}</p>
                            {{ /if }}
                            <div class="career_form_item_field">
                                {{ if type == "text" }}
                                    <input type="text" placeholder = "{{ instructions }}" name="{{ handle }}" value="{{ old }}" />
                                {{ /if }}
                                {{ if type == "textarea" }}
                                    <textarea name="{{ handle }}" placeholder = "{{ instructions }}" rows = "20" value="{{ old }}"></textarea>
                                {{ /if }}
                                {{ if type == "assets" }}
                                    <input class="career_form_upload" type="file" name="upload" />
                                {{ /if }}
                            </div>
                        </div>
                    {{ /fields }}
                    <button class="career_form_button">Skicka</button>
                {{ /form:career }}
            </div>

This is: resources > forms > career.yaml

title: Career
blueprint: careerform
fields:
  upload:
    type: asset
    container: uploads
    folder: users

This is the form blueprint if relevant: resources > blueprints > careerform.yaml

title: Careerform
sections:
  main:
    display: Main
    fields:
      -
        handle: name
        field:
          html_type: text
          character_limit: 40
          type: text
          instructions: Namn
          localizable: false
          listable: hidden
          display: name
          validate: required
      -
        handle: email
        field:
          html_type: text
          character_limit: 50
          type: text
          instructions: 'Din e-post'
          localizable: false
          listable: hidden
          display: email
          validate: required|email
          input_type: email
      -
        handle: message
        field:
          type: textarea
          instructions: Meddelande
          localizable: false
          listable: hidden
          display: message
          validate: required
      -
        handle: assets
        field:
          container: uploads
          mode: grid
          restrict: false
          allow_uploads: true
          max_files: 1
          type: assets
          instructions: 'Upload your asset here'
          localizable: false
          listable: hidden
          display: Assets

Thanks in advance for the help!