eBay probably has an HTTP link to a script mixed in there somewhere that they will eventually get to and switch to HTTPS.
I'll bet you are using the latest Chrome browser. Google has taken it upon themselves to fix the internet by force by making Chrome warn on everything since they feel the rest of the world is moving too slow on security issues (some of which are real). Unfortunately, Google's approach is to make unilateral changes, which then cause users to complain to websites, and forces those websites to act or risk losing those users who think the website is at fault, insecure, and a hacker haven.
That is a "you" problem for now. There is nothing for eBay to fix (other than getting around to converting everything over to HTTPS eventually - not when Google says to)
There should be some sort of settings in Chrome (or Firefox if that is what is the cause) to "tone down" those security warnings/blocks. (in the strictest you would be advised to change he settings back to full paranoid level when not revising an item)
Would be easier to just use another browser that doesn't complain.
What browser? Can you post a screenshot of the error message warning?
