Unknown sender message

[Mminister]

Hi can anyone solve this issue please?

I have a Sony Xperia z2 and ocassionally when I open my messaging app it will display a message right at the top for about 2 seconds saying something like <</unkown sender/>> and then it will disappear. It doesn't come up evrytime my open my app and it tends to do it the first time I open the stock text messaging app after a while or if I've restarted/ lost charge recently. I don't know what the message is as it disappears too quickly to even click on it and I'm not 100% on the message text but it is not like any other text messages in the app.

Thanks for your help  

[FixtheNet]

This has been happening to me as well, and I have a Huawei. No matter how I change my settings, or speak to techs, nothing stops, identifies or opens them.

[LittleCheese]

I had one of these messages this morning in capitals UNKNOWN SENDER, I have a Huawei, it was there for a couple of seconds and then dissappeared