The school newsletter service has been opened, why is it sometimes delayed to accept short messages?

(1) The short message of "Xuexuntong" is sent through a professional and mature short message platform, and the probability of missing and delay is very small; Normal can receive information within 30 seconds. At present, the system only supports mobile phone numbers in Guangdong Province. (2) For example, during the peak period of short messages (students go to school and leave school), holidays, etc. Some short messages may be delayed due to busy network, so there is no need to resend them. Other reasons for unsuccessful information transmission: the other party's power off, not within the scope of network service, arrears of downtime.