Iphone can't send text messages, and there are exclamation points.

If you can't send SMS, you may have the following problems:

Which carrier's SIM/U-SIM card are you using? Is there something wrong with the U-SIM or SIM card? If you are a Unicom card, I suggest you go to the business hall and spend tens of dollars on that kind of "iron card" for iPhone, and 60 yuan will be naked. By the way, there is a popular saying here: "The stupidest in the world, Apple is equipped with a mobile card".

I have encountered this situation before. Later, it was found that it was much better after changing the card because of improper operation when cutting the card. But when the mobile card was placed on Apple, there was a problem with the signal circle. Before we bought bare metal in Unicom or during the contract period, we could get the signal circle for free. Besides, mobile 3G is not as powerful as Unicom, and it is said that mobile will have a 4G network.

3. Is your Iphone MMS setting correct? The three operators set up MMS in different ways. The correct answer should be whether these English inputs match your carrier card.

4. Apple's mobile phone standard is W-CDMA. For the time being, only Unicom is fully supported by the three operators, which means that only Unicom is W-CDMA.