First idea: Create a new model at the ST10 and try to bind to this.
Second proposal: If this is not working, remove battery from ST10, wait 30sec or more (some kind of HW reset) and plug in Battery again. You have to set date/time and then try to connect to a new model.
If nothing works, find another guy with Q500 to meet. Try to crossconnect the copter (his q500 with your ST10 and your ST10 with his Q500). So you can find out if transmitter and/or receifer is working of defective.
First time user. Successfully connected to the GUI and the ST10+ yesterday. Today, on my first attempt to fly, the Q500 4K would not connect to the ST10+. I then followed the "bind" procedure to no avail. I am now attempting to reconnect to the GUI, also with no success. Can anyone Help?