Adding HA cluster to fortimanager

Hi all,

I have tried adding an HA fortigate cluster to the fortimanager, using the dedicated management interface (have tried outside and inside interface aswell with same issue)

When adding, it detects the cluster, finds the name and IP and the fact its a cluster ETC then at this stage I get the error:

(success) Discovering device (success)Creating device database (success)Initializing configuration database (FAIL) Retrieving configuration Retrieving support data Updating group membership Successfully add device

with error: "Failed to reload configuration. duplicate"

Anyone know why this is occurring? Can't find much relating to this particular error.