I had several domain, but out them, 2 was not display adsense ads. Did it block by adsense? I check all setting was correct. How to check the domain been blocked?
You can try with this tool: http://www.labnol.org/google-adsense-sandbox/ You type in your domain name, press "show google ads" button, and if the ads don't show on next page, it means this domain has adsense disabled.
Thanks for the link. I check my domain been disable by adsense. How to enable it again? Need to send ticket to adsense?
Yes probably, I guess you need to have a good reason, like you bought the domain name and it wasn't you who had problem with adsense previously, etc.