The item cannot be listed or modified. The title or description may contain improper words, or the listing or seller may be in violation of eBay policy

This is a generic eBay error caused by either violation of the eBay selling policy or a restriction on your eBay account.  For example, the error may return if you use email or social media links in a title or description. To solve the problem, you need to check the title and description text and exclude restricted words.  

Note: The error may also be shown along with another error. In this case, you need to pay attention to the second error.