Hello Sanket,
For SX20 you will get all msgs in event/all.log file.
As its name it will have all the information about what is happening on device.
If you know the time you can directly check for that time stamp, if not then you need to check all Register msgs and what happened just before that to see why the device De-registered.
Thanks
Please rate if it is helpful...
Thanks
Please rate if it is helpful and mark as accepted solution if applicable....