ShortMessage:Security policy violation. Description contains HTTP resources, which are not secure.
LongMessage:eBay security policy only allows HTTPS resources in listings, not HTTP. Please update or remove any HTTP resources. \nDescription"]
Explanation and resolution:
The long and the short of it is that somewhere in your listing there's an http: instead of an https:. These days, with the ban on active content and links inside your listing, it's most likely an image.
A great tool for finding the issue when you get this error is https://bulkchecker.i-ways.net/ebay/en-us.
eBay introduced new requirements for product images, custom listing templates and item descriptions with their Summer 2017 update (eBay Summer 2017 update). This page goes into further details of the issue.
You can also learn more about the HTTPS standard at the Browser Security Standards page.
eBay has stated that new, or existing non-compliant HTTP listings (any that contain non-secure content or assets) would be blocked by eBay as of September 15, 2018.
eBay has a built-in tool to identify any eBay listings which are flagged for HTTP issues. But, as mentioned above, you can also go to https://bulkchecker.i-ways.net/ebay/en-us for an analysis of any eBay listings.
If you are running an old SureDone stock template for your eBay listings, you may need to update it. Here are additional SureDone resources on this subject: