Mlag from Fortiswitch core to unifi access switch

I am trying to set up mlag from my core fortigate 1024E switches to a unifi 48 pro poe device using fiber connections.

We were able to get the connection to work at one point for about 15 minutes. Someone made a change and it stopped working. Currently the config of the mlag on the Fortiswitch side is:

edit mlag 6
set mode lacp-passive
set mclag enable
set lacp-speed fast

This is direct from CLI on the switch since we had a short time of mlag working all changes have been on the fortiswitch side. I am not sure what change was made because I am not sure what the config was when it was working.

Any pointers would be helpful