Losing network operator on Samsung Galaxy SIII mini For some time now (I think it's from the latest Android update) I have this problem,
that time to time (on daily basis) people can not reach me, like I would lose connection to the Network.

I get an SMS after some time about all the calls I did miss. Sometimes I have a hard time to call as well.

I did call my operator, and they didn't had any report like this so far, and I did call Samsung service, and they didn't know about this issue, so I guess is on my side.

If you have any idea what would the problem be let me know.
I experienced a similar problem, and it was caused by physical activity making the SIM card coming slightly loose, just enough so that the phone couldn't read it reliably. Try turning the phone off completely, removing the SIM card, reinserting the SIM card, and then restarting the phone.

If that makes the problem go away (at least for a few days), then it probably is the SIM card coming loose: maybe that specific phone is on the largest extreme of manufacturing tolerance, and the SIM card is at the smallest extreme. In this case, a little paper inserted alongside the SIM card, on the side without the contacts, could provide a more lasting fix.