Hello @rubenvankempen and thanks for reaching out to us!
A 403 usually means the firewall is blocking an action it thinks could be malicious. Since we know Elementor is not malicious, let’s try Learning Mode to resolve this.
From the Wordfence Dashboard click on Manage WAF. Then you will see Basic Firewall Options > Web Application Firewall Status. Change the option to Learning Mode. Now perform the actions that were causing issues. This will help Wordfence learn that these actions are normal and it will allow them in the future. After you have finished performing the actions, switch the WAF from Learning Mode back to Enabled and Protecting. Now test to see if these actions work correctly.
https://www.wordfence.com/help/firewall/learning-mode/ is an amazing resource for learning more about the WAF and learning mode.
Let me know how it goes!
Thanks!