This item cannot be listed due to violation of eBay policies. Please check with eBay the reason behind this or click on “Show Error Details”.
There could be many reason for this message. The title could have issues or even the description. The item maybe a restricted item on eBay, or it's in the wrong category causing an error on eBay's part. it could even be seller limits have been reached, or the account is suspended. By clicking the error message you can usually find out what's causing the issue and fix it.
The next step would be to contact eBay if this exists on multiple items in a manifest, or all of them; that usually indicates a suspension. But again, there are many reasons for this error.