MCLAG e Fortilink - always appear in a disconnected state

I have created an MCLAG between the two switches using the graphical interface. Each switch is connected with one port to a cluster of 100F firewalls in active-passive mode. For now, I’ve only connected a single physical cable because I don’t fully understand the situation yet, so I’m keeping things as simple as possible.

I don’t understand why all the links always appear in a disconnected state.

Additionally, I would like to use multiple LAGs, both between the switches and also between the firewalls and the switches, but I’m not sure what the correct configuration should be.

My firewall is running firmware v7.6.3 build3510 (Feature), and the switches are on S248EF-v7.6.2-build1085,250526 (GA).