What color is displayed when the message is closed?

In the WeChat function, the close key is displayed in gray when it is closed, and green represents the open state.

Message non-delivery report. See if there is a green dot in the upper right corner of your message. If there is a green dot, it means that it was sent successfully.

Time will be transmitted to the mobile phone. If the green dot is not displayed, even if the other party is not turned on.

Or the number is down. If the message fails to be sent, the message will not be displayed.