In order to fix shutter 6D error 30, you need to start by turning off the camera. You then need to remove the battery and the lens and then wait for around 30 seconds. After this, you can put the battery back in and turn the camera on again.
Just take off the lens and manually move the shutter up. See if there is something blocking the path of the shutter (behind the shutter) (I found something blocking the shutter. I took it off and voila, the camera was working again.