BC66 hangs when switch to automatic operator selection +COPS=0

if I use AT+COPS=4,2,“26201”,9 to manually select operator, it works w/o any problems. But I decided to switch to automatic mode by command AT+COPS=0, module hangs. Making CGATT=0 doesn’t help. Or it is better to use CFUN=0 before COPS and then switching back to CFUN=1 ?
Module hangs only if there exist network registration.

hi, Maksym_Nechyporuk:
Did your device or module fail to register with the network?
If you need to perform a specific test, you can run the “COPS” command to configure the test. but not, just run the “AT +cops=0” command.
If you encounter any errors, I suggest that you attach a log of the execution.

device was registrered already, but with +COPS=4
I have discovered that +COPS=0 works if device is de-registered, CGATT=0, CFUN=0. After that I changes setings of COPS w/o any hangs.

hi, Maksym_Nechyporuk:
If you execute CGATT=0 or CFUN=0, the module cannot enter the idle state.

I’m not executing test command COPS=? but write command COPS=0.
Accrding to Notes No. 2 This write command …otherwise an error will be returned. But device hangs is “returned”.