MC7700 - waiting for network personalization PIN??

Hello ,
I have a strange problem
I have 10 modems MC7700 and 7 of them work just fine
the other 3 give me this massage whenever I want to make a connection
“waiting for network personalization PIN” .

I’m using the same SIM for all 10 modems (to be sure there isn’t any problem with the SIM )

what could be the problem?
how can I fix this ?

Thanks ,

what is the output of AT+CPIN? in the defected modems?