SIM808 loss connection and doesn't reconnect

Hello ,
I have a small project using the SIM808 with arduino zero

everything work great for 4 weeks
suddenly it stop sending me data
when I open the terminal I see it disconnected from the network

but now when he try to reconnect I get nothing

Error in netwrok - goinig to reconnect!
AT+CPIN?

+CPIN: READY

OK

AT+CREG?

+CREG: 0,1

OK

AT+CREG=1

OK

AT+CGATT?

+CGATT: 1

OK

AT+CGATT=0

OK

AT+CGATT=1


OK
AT+CSTT=internet

ERROR

AT+CIICR

ERROR

AT+CIFSR

ERROR

any idea why ?
am I missing a command or something ?

this isthe same order of command I use on boot and it works
Thanks ,