Ads created in a specific ZONE is not showing up on my website although the banners/campaigns are activated/linked and all other configuration is OK !
I found that the Ads created on OpenX takes some time (hour+) to appear on my websites, only if you are using zones, if using direct access instead the ads will appear right away
NOTE: DON'T USE OPENX HOSTED SERVICE SINCE IT IS NOT RELIABLE, The self hosted openx server is so much better
If it is still not showing up after several hours check the link below
If you are using AdSense with OpenX check this link
Another useful link