In reply to Kristof.

You can force your site to redirect from http to https in 2 ways.

Use a WordPress HTTPS plugin https://wordpress.org/plugins/wordpress-https/

Update rules in your site's .htaccess file
https://help.dreamhost.com/hc/en-us/articles/215747758-How-do-I-force-my-site-to-load-securely-with-an-htaccess-file-

Update Google Analytics
=======================

First update settings at:
https://analytics.google.com

Go to ADMIN, select property and then change the http:// to https:// for the Default URL at:
PROPERTY/Property Settings
VIEW/View Settings
Then go to WordPress and change Google Analytics Settings:
First: Clear Authorization
Then: Reauthorize again and check that General Settings\Default URL: start with https://
Save the changes.