FIREL ALARM PANEL KENTEC SERIES 6000-BS EN54-2

Hello
In a big system fire alarm system about 4 panels with 4 reapeters i have an anexpective problem. The panels are adressable and all panels and repeaters connect with network system i mean each panel have node number and each panel connective to the other. One panel of them have every time the same problem << autolearn fault>>. i do all resets the big reset normal reset but nothing normal. I put access code 3 go to menu find <> from the menu, ask me to put the pin to enable to can do the autolearn the panel. i do this but nothing normal the same broblem every time.
please help me