SIM800L - Cannot fix send SMS

Hey all.

I recently bought a GSM Module with SIM800L (I'm from Europe).

When I make "AT-COPS" to define my OP, sometimes its 0, other times its 1 (Vodafone). I cannot send 'AT-CMSG'.. it says error and I beleive its because I keep loosing connection to my operator.

What do you guys think?