EST3 database download error on 3CPU

[namlashs]

Dear all,
I have 23 est3 panels at our site. I regularly make changes as per site requirements and successfully download the databases to the required CPU in the cabinet except in 3 panels out of those 23.
When i try to download the database to any of these three CPU's, it says: "please connect to the following module.." (see attachment)
Note that i can access the loop cards in these cabinets through the rj11 directly connected to the cards but not through networked when connected to CPU.
Can anyone help me with that?

received_1601622083213004.jpeg

received_1601622083213004.jpeg

[Nirujan]

check is there any network related troubles, if yes solve it, and check all the panels firmware versions, it should be same for all the panels which is connected in network.