I only see this show up on my phone if there is either no SIM in it, or I've put one of the spare SIMs in that isn't activated. So basically it's telling you that you will have no cell service to make/receive calls or texts. Regulations require that you still be able to place emergency calls (911 in the US) on any cell phone, regardless of the presence or absence of carrier service.
If the phone sometimes works and other times pops up this message then you should start with verifying the SIM and carrier service.