Receive repeated sms messages


I have been testing sms transmission with mangoh WP7702, I used my cell phone to send a sms text to mangoh once, but without sending further messages, after a few minutes, the module recevied repeated sms message once again, please see the following screenshots:

received “Hello” twice,

received “Test nihao2” twice,

I wonder whether it is the issue caused by mangoh or the sending unit?


how about sending a SMS to WP77 itself?