It's probably an ID10T issue on jewbay's side.
From comments:
Its not just solder. eBay has (had?) an international shipping program where they'd confiscate/divert anything deemed "hazardous", refund the buyers, and then have a 3rd party re-auction it to domestic-only buyers.... they'd confiscate anything with vacuum tubes under the assumption they're all full of mercury (they're not, only certain tubes- maybe less than 1% of them do).
Another one:
It's probably lead based solder that's the issue .... I buy all my solder from ebay and my Rosin to, several different types of each one, so it's NOT as if solder is just banned
ugh. At least I'm still free to buy and eat the stuff here.