Adding firewall to Device Rule failed

hi dear

i have 2 firewall, fortigate version 6.4.2 and 6.2.3,

i added my 6.4.2 device to device rule successfully but when i trying to add 6.2.3 device a get this error.

both device pass validation procedure.

how should i solve this problem ?

config system console	8278: unknown action 3\ncommand fail. return code -1\n
set output standard		Not Executed
end		Not Executed
show full-configuration		Not Executed
config system console		Not Executed
set output more		Not Executed
end		Not Executed

Reason for failed:

Problem while fetching configuration from device :::2

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