7.4.6 Fortigate VM not adding to 7.6.2 Fortimanager VM

Hi All,

I am facing a problem that 7.4.6 running Fortigate VM (running on EVE NG) is not adding to the Fortimanager VM (running on VCenter)  running 7.6.2. While adding the FGM IP from the fabric connectors in the fortigate VM blow error is prompting 

" The FortiManager's access to the FortiGate will be authenticated by the FortiManager certificate. The serial number from the certificate must match the serial number observed on the FortiManager. Could not connect to the FortiManager to retrieve its serial number "

Can anyone suggest me a workaround for this ?