How do i add <meta http-equiv="Content-Security-Policy" content="upgrade-insecure-requests"> to flask-bootstrap template

Am not getting the expected results through my browser because of This request has been blocked; the content must be served over HTTPS.

I have tried adding this

{% block head %}
{{super()}}
<meta http-equiv="Content-Security-Policy" content="upgrade-insecure-requests">
{% endblock %}

Which has worked for other people

'https://matic.herokuapp.com/' was loaded over HTTPS, but requested an
insecure XMLHttpRequest endpoint
'http://matic.herokuapp.com/status/9092ba37-591e-4e73-b9e3-0ad9bef26cb1'.
This request has been blocked; the content must be served over HTTPS.

This would mean that you're dynamically generating an http url instead of https. When I looked at your code, you're using

return jsonify(
       {}), 202, {
       'Location': url_for(
            'taskstatus', task_id=task.id)}`

to create a dynamic url. Can you update this to

return jsonify(
       {}), 202, {
       'Location': url_for(
           'taskstatus', task_id=task.id, _external=True, _scheme='https')}`

and respond with the result. Not the difference in url_for