In case you run into trouble with your web application firewall and running Mautic:
If WAF is set to “balanced”, it will also check post data: this prevents Mautic to save emails and landing pages successfully. Pressing the button to save doesn’t work, the button gets greyed out and becomes inactive.
Your webserver protocol will show some errors related to the firewall.
These are the rules, that would need to be disabled for Mautic in order to run again:
You could disable those rules just for your Mautic instance, or - depending on your needs - switch the firewall mode to “fast”. This will not check the post data. It will also work without excemptions.
Of course, switching of firewall rules is tricky - they are there for a reason. However, Mautic seems not to work too well with them.