The sending failed because the sending of short messages was restricted.

What you want to ask is what caused the failure of sending short messages because of the limited sending? The cell phone signal is not good or the short message sending frequency is too high.

1. Bad cell phone signal: the cell phone signal is unstable or in the blind area of the cell phone, which will lead to the failure of sending short messages and a restriction prompt.

2. The frequency of sending short messages is too high: In order to prevent bad behaviors such as short message bombing, operators usually limit the frequency of sending short messages, which will lead to the failure of sending short messages and a restriction prompt.