ShipScript has been an eBay Community volunteer since 2003, specializing in HTML, CSS, Scripts, Photos, Active Content, Technical Solutions, and online Seller Tools.
That will occur when using eBay's Quick listing tool or eBay's new Unified listing tool because both strip off style sheets. eBay's latest Motors listing tool performs the same way. Rather than using the "Linked Video (code)", use the "Linked Video (editable)". The editable version applies inline styles rather than a separate stylesheet. The Play arrow will be visible, but won't change color.
In all cases, the code will not function fully in the eBay app (nor will any links). The visitor must copy the displayed URL, open a browser window outside of the app, and paste the URL in the browser to run the video.
On the tool, there are some different formats offered to the left of the code window.
https://isdntek.com/tagbot/YouTubeConverter.htm
The HTML created for the "(code)" version contains a separate block of style codes. These styles provide the dynamic start button that acts like a YouTube start button. But some of eBay's listing tools will strip out that block of style code, so not only will the button disappear, but the whole video arrangement will fall apart.
The "(editable)" version uses inline styling that eBay mostly leaves in place. The start button won't be dynamic, but it should still click like the link that it is. There are two ways to paste the editable version in your listing: 1) use the code "select" button to highlight and copy the code from the code window and paste it into the HTML view of eBay's description editor, or 2) use the video "select" button to highlight and copy the rendered video block and past that into the standard editing view of eBay's description editor.
eBay's description checker exists in only the Business listing tool. eBay did not import it into the new Unified lister.
If you need to check, or fix, your descriptions, you can paste the item number (for an existing listing), or the HTML of a new description, into the top box on this tool:
https://www.isdntek.com/ebaytools/ActiveContentSandbox.htm
Checkmark 4 to 6 fixit boxes, click "Scan", and scroll down to the "Filtered" tab to pick up the repaired HTML code that can be pasted back into the HTML box of eBay's description editor.
The HTML editor on eBay's Unified Lister is harder to get to, and part of their warning is to prevent adding the types of codes that eBay bans.
 
@shipscript wrote:eBay's description checker exists in only the Business listing tool. eBay did not import it into the new Unified lister.
If you need to check, or fix, your descriptions, you can paste the item number (for an existing listing), or the HTML of a new description, into the top box on this tool:
https://www.isdntek.com/ebaytools/ActiveContentSandbox.htm
Checkmark 4 to 6 fixit boxes, click "Scan", and scroll down to the "Filtered" tab to pick up the repaired HTML code that can be pasted back into the HTML box of eBay's description editor.
The HTML editor on eBay's Unified Lister is harder to get to, and part of their warning is to prevent adding the types of codes that eBay bans.
 
Thanks. That's what I was able to find also. Except no quick tool to quickly fix like there was in the past. Unfortunately I am not fluent in html.
-Lotz
If you tend to copy your descriptions from other sites, you will probably need to clean it before posting the listing. eBay does make it a lot of work, but if you can follow the four clicks to get the HTML from your listing, it can be copied and pasted into the Sandbox tool that I posted, and the tool will fix the code. Then copy/paste the repaired code back into the same HTML box on eBay. No fluency required, just a lot of clicking and the ability to find the HTML box on eBay.
I bulk scanned your 1362 items and found these 4 that contained external links:
https://www.isdntek.com/ebaytools/ActiveContentSandbox.htm?153935218167
https://www.isdntek.com/ebaytools/ActiveContentSandbox.htm?403872686069
https://www.isdntek.com/ebaytools/ActiveContentSandbox.htm?403877292320
https://www.isdntek.com/ebaytools/ActiveContentSandbox.htm?403884036718
Each will open in the sandbox tool. Scroll down and open the "Filtered" tab to find the repaired HTML. If you don't want to copy the HTML, then click "Popup Preview" and copy from there.
Some of the links had already been modified (incorrectly) causing them to take on the the link of the page where viewed. I manually added a filter to clean those kludges from the preview screen on the above links. Maybe I need to make a simple cleaner tool....
