I can not get trial license

I downloaded Fortinet Firewall VM version 7.6.4. I want to use it for testing purpose.
Although I started the VM and accessed the management console, I see the message "VM is not licensed or license is invalid for current VM configuration. Upload a new license or reconfigure the VM. I want to get just trial license.

I checked following past post. But it does not solve the issue. I also contacted support, they requested me to post my issue in this community site.

https://community.fortinet.com/t5/Support-Forum/Requesting-Forticare-Trial-license-proxy-null/td-p/357387

Can somebody help to get a trial license?
My serial number is FFVMEVWJXNQCX3FE.