We have the same issue with Amazon orders. We don't sell on eBay. Etsy
and Shopify work but all shipping fees are $0 for Amazon orders.
Shipstation has been horrible this year. The new UI is terrible and
there are way too many glitches.
So, I just tried again and this time it worked. It feels like it was a
problem on Etsy's side. Maybe? Anyway, resetting the marketplace
connection no longer gave me a 404 error.
I have the same issue. Orders stopped syncing since yesterday. The error
I got is "An error occurred attempting to update orders: The remote
server returned an error: (403) Forbidden" When trying to reset the
marketplace connection, I'm getting this ...
One more issue to add to the pile. Product photos are no longer
displayed. We get a grey box instead. It doesn't happen with all orders.
It seems to be random.