Simple website deploy from GitHub

Hi this maybe a rudimentary mistake, but my deploy failed, perhaps because I’m using external domain registrar? My page was built from github repository with success and is accessible via myname .github.io. Now I just need it to point to my new custom domain.
Here’s the error:

4:22:11 PM: failed during stage ‘building site’: Build script returned non-zero exit code: 255

I have the following DNS records settings in Netlify:

www . mynewdomain . org
3600
IN
CNAME
myuser . github.io
mynewdomain .org
3600
IN
NETLIFY
infallible-wing-3fc0a6.netlify.com
www. mynewdomain .org
3600
IN
NETLIFY
infallible-wing-3fc0a6.netlify.com

It seems like my domain is recognizing an old build and notrecognizing a subdomain or something. MANY THANKS for any thoughts you might have.

hey there, if you run a quick search on “255” you’ll see there are a couple of other folks who have had this error before.

Is this helpful at all?