Microphone on keyboard is dim and no longer works

The Microphone on keyboard is dim and no longer selectable on my I-Pad Air 2. 2 days ago I was dictating into e-mail, Evernote etc and everything worked fine. Now 2 days later the microphone on the keyboard is dim and is no longer selectable. What happened? I tried re-setting, turning on and off, turning off Bluetooth, Cellular etc. I had read online it might be an OS issue. Can anyone fix please?

Kind Regards

Romefucan