Use this article to fix a listing that shows export failed because eBay rejected its Size value, and to understand why this started happening. It applies to any item with a Size field, in any category, not just clothing.

What you'll do:

eBay is standardising size values across Apparel & Footwear listings — this applies to any listing with a Size field, whether it was created directly on eBay, through Listing Monster, or through any other tool. Instead of accepting any typed size (like "UK10"), eBay now only accepts a value picked from its own fixed list of standard sizes (for example XS, S, M, L, XL).

eBay rolled this out in two stages. From June 2026, eBay began automatically converting listings with clear, high-confidence size values (for example, "Small" becomes "S"), and started flagging unclear or invalid entries such as "See description" or "N/A." From August 2026, eBay began blocking or holding any new or existing listing with a non-standard or missing size value — this is the stage now in effect, and it's why you're seeing export failed on affected listings.

You don't need to change anything about how Listing Monster sends size data. You just need to correct the Size value on any listing eBay has flagged, using eBay's standard options — this article shows you how.

You can spot affected items from your Items table, or from inside an individual listing.

To confirm a specific item failed because of its sizing, click into it and check the eBay tab — a red ! icon next to the tab name means there's an export error to look at.

Once you've opened the item with the sizing error, you'll fix it from the eBay tab.

On the eBay tab, scroll to the QC Violations panel under History. This shows the exact reason the export failed — for example, "UK10 (Top), UK6 (Skirt)" is not a valid value for Size. Select a value from the available options.

Scroll down the eBay tab to the Required Item Specifics section.

Some items — like a co-ord set with a UK10 top and a UK6 skirt — don't fit neatly into a single Size value. In this case, select whichever size is most relevant to the listing, and add the other piece's size to the item's description so buyers still have both.

Saving your Size fix doesn't re-export the listing on its own — you need to trigger the export again.

For most items, this is all you need to do.

This starts the export attempt again using your corrected Size value.

If you've already re-run the current steps and the item still shows export failed, it likely failed at an earlier stage of its merchandising strategy — a merchandising strategy is the set of pricing and listing steps Listing Monster runs for an item over time. In that case, re-assign the strategy instead of re-running it.

✅ Once the export succeeds, the red ! clears from the eBay tab and the sizing error disappears. Your item's status in the Items table updates from export failed to its next status (such as Active or Scheduled), confirming it's back on eBay.

Choose whichever size is most relevant to the listing, and add the other piece's size to the item's description. eBay's Size field only accepts one value, so the description is where the second size lives.

Re-assign the strategy instead. This usually means the item failed at an earlier stage of its merchandising strategy, and Re-run Current Steps alone won't push past that — use Re-assign Strategy from the ⋮ menu on the Merchandising Strategy tab.

eBay removed the option to enter custom size text on listings as part of its size standardisation rollout. You now need to choose from eBay's fixed list of standard sizes (such as XS, S, M, L, XL) in the Size field.

It can affect any eBay listing with a Size field, in any category — not just co-ord sets or Women's Clothing. If an item's export failed message mentions Size, this is the same issue.