Lg G3 not connecting to mobile network! help please

Hi
After a hard reset, I got a circle stuck spinning on the signal in the bar
I pressed on the Select Automatically - nothing happened
tried the "search networks"
I got some networks
but when i try to connect to the network it says:
"Unable to connect to this network at this time.
Please try again later."

I tried to hard reset
that doesn't really help
any suggestions ?
thanks