If your board was letting you write, but isn't now, there's two things you can look for!
One, check the indicator light that's on the right side of your board. Is it green or red?
If it's red, you need to check the USB connection. You can unplug from the board and plug it back in. Then, do the same at the computer!
If the light is green, there's a good chance you need to restart your computer!
Why? Well, the SMART software is pretty old and likes to lock up in the background. Usually, a restart fixes this issue quickly!
If you try this and you still can't write, please put in a ticket so we can help!