No IP connectivity with LAG between FortiGate 200D and Ubiquiti EdgeSwitch

[sbatbs2]

Hello all. We have a FortiGate 200D (IP 10.10.0.2) connected to an Ubiquiti EdgeSwitch (IP 10.10.0.5). We want to connect both devices with Link Aggregation (LAG) for tagged VLANs, but it is not working. According to various documentation we found online, we created a new interface as "802.3ad Aggregate" with ports 15 and 16 and no IP. And the ports show up with an established LACP state, ASAIEE partner state and matching IDs (see config and details below). And with diag cmd, we see LACPDU packets from the switch.  But we cannot ping or communicate with the other side by IP. We have also tried changing lacp-mode to static (on both ends) or passive on the FG, enabling (in various combinations) broadcast-forward, l2forward, stpforward, and/or vlanforward on the LAG, put the LAG in a new zone, tried to add the LAG to the lan interface but that option is not available, and finally add LAG<->LAN policies ... all with no change to IP connectivity. In case it matters, the FG is not in transparent mode and not using multi-domain. LAG between two EdgeSwitches works. We saw one forum post that looked like another user had LAG working when they were in a multi-domain configuration, but we could not find anything to confirm that configuration was required. Can anyone please confirm if we must use a multi-domain configuration and/or provide the configuration for LAG to work in a root-only domain.

Thank you.  - - - Config Section - - - # show system interface lag-test config system interface     edit "lag-test"         set vdom "root"         set allowaccess ping         set type aggregate         set member "port15" "port16"         set lacp-mode active         set role lan         set snmp-index 10     next end # diag netlink aggregate name lag-test ... slave: port15   link status: up   LACP state: established   actor state: ASAIEE   actor port number/key/priority: 1 17 255   partner state: ASAIEE   partner port number/key/priority: 23 66 128   aggregator ID: 1   speed/duplex: 1000 1   RX state: CURRENT 6   MUX state: COLLECTING_DISTRIBUTING 4 slave: port16   link status: up   LACP state: established   actor state: ASAIEE   actor port number/key/priority: 2 17 255   partner state: ASAIEE   partner port number/key/priority: 24 66 128   aggregator ID: 1   speed/duplex: 1000 1   RX state: CURRENT 6   MUX state: COLLECTING_DISTRIBUTING 4

[Philippe_ASTIER]

Try switching the LAG to static in the Fortigate, this is the only configuration I could use so far.