Weird new logo

[Benjamin Ryan]

So I was working today and I lose signal quite often in my building. I noticed a new symbol beside where I'd have alarm, silent or WiFi notification. It looks like a 'cancel' logo and it won't go away. I tried a restart a couple of times no joy. I'm using a HTC M8 with android version 5.0.2.

 

[Aquila]

It means that notifications are set to "none".