There is nothing in the message, but a red exclamation mark is displayed. What happened?

Indicates that there is an unsuccessful message to send in the short message. There may be several reasons for this:

1, generally because the network is unstable or there is no network. Confirm that the network connection is normal and then resend it.

2. The content that violates the rules in the sent information is blocked and can be retransmitted in another way or phrase.

3. The other party has blacklisted you, but the information you sent can't be received by the other party, so the other party needs to lift the blacklist restriction.

Short message is a telecommunication service in digital mobile communication system. It is a non-real-time and non-voice data communication service to transmit text or digital short messages through the signaling channel and signaling network of mobile communication system. The short message can be initiated by the mobile communication terminal, the short message platform server of the mobile network operator and the network service provider SP interconnected with the short message platform of the mobile operator.

relevant information

At the beginning of the development of short message service, the sending and receiving of short messages started from mobile phones, and finally went to mobile phones, passing through GSM network /CDMA network, short message center and other network elements; With the emergence of short message on demand and customized services, mobile phones, internet sites and short message value-added service systems can send short messages to each other. Internet site and short message value-added service system have become new network elements, while GSM/CDMA network and short message center still maintain the core position of short message network.

With the emergence of PHS mobile phone based on fixed telephone network in China, the short message service has been extended to fixed network, and the terminal is no longer limited to mobile phone. PHS mobile phones or dedicated fixed terminals can be used as the sender and receiver of short messages, and the network foundation is no longer limited to digital mobile networks such as GSM/CDMA networks, but fixed networks can also be used as the network foundation of short messages. The elements of short message network have changed greatly.