diff --git a/documentation/changelog.rst b/documentation/changelog.rst
index 1288983ec..40583a3dc 100644
--- a/documentation/changelog.rst
+++ b/documentation/changelog.rst
@@ -17,6 +17,7 @@ New features
 
 Bugfixes
 -----------
+* Fix charts not always loading over https in secured scenarios [see `PR #716 <https://www.github.com/FlexMeasures/flexmeasures/pull/716>`_]
 
 Infrastructure / Support
 ----------------------
diff --git a/flexmeasures/ui/templates/base.html b/flexmeasures/ui/templates/base.html
index edbf456ee..3198b4a8f 100644
--- a/flexmeasures/ui/templates/base.html
+++ b/flexmeasures/ui/templates/base.html
@@ -11,6 +11,9 @@
     </title>
     {% endblock head %}
     <meta charset="windows-1252">
+    {% if flask_env != 'development' and flask_env != 'testing' %}
+      <meta http-equiv="Content-Security-Policy" content="upgrade-insecure-requests">
+    {% endif %}
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <link rel="icon" href="favicon.ico" type="image/x-icon" />
     <link rel="shortcut icon" href="/favicon.ico" type="image/x-icon" />
diff --git a/flexmeasures/ui/utils/view_utils.py b/flexmeasures/ui/utils/view_utils.py
index ae622ba77..0c9bf07da 100644
--- a/flexmeasures/ui/utils/view_utils.py
+++ b/flexmeasures/ui/utils/view_utils.py
@@ -25,6 +25,7 @@
 
 def render_flexmeasures_template(html_filename: str, **variables):
     """Render template and add all expected template variables, plus the ones given as **variables."""
+    variables["flask_env"] = current_app.env
     variables["documentation_exists"] = False
     if os.path.exists(
         "%s/static/documentation/html/index.html" % flexmeasures_ui.root_path