Why can't Sony LT26w(Xperia acro S) send short messages?

First, let's see if the flight mode is set and the radio is turned off. In this case, both text messages and phone calls are unacceptable.

Press the power off button, and an airplane icon will appear, which is called the function of turning off the radio. If it is closed, just click on it.

Secondly, it depends on whether there is something wrong with your mobile phone card or the mobile phone itself. The card was not put away before, and the mobile phone did not recognize the card. The phone will prompt that there is no SIM card.

And ..... see if your card can still make calls, and whether it has stopped. . .