He was probably out of range. This happens to me too.
But sometimes, they send a message. Then you can communicate with them
Slightly different version of a similar issue today. This plane did everything right, and I heard th audio of Turkish Airlines, but it popped up as unknown, and I had no commands in the menu in which to respond.
I’ve also had this happen but when I click on the plane they appear back on and I’m able to communicate with them.
I tried that, but it didn’t work. I tried from the menu, from touching the plane…even tried going to ground and back and to another plane and back. Nothing fixed it.
And it still says they are on your frequency correct? The second picture is a different bug. I used to experience this in between updates but not recently.