I've had this issue before now it's happening again.
When I try list something new or relist an item on .com it's forcing me to sign in to .ca in order to submit the listing. It doesn't happen with my store account, it happens with this account that is not a store.
I'm guessing this is a glitch. I hope it's fixed soon.
Sign in on eBay.ca
Then - after you are signed in - change the URL to show .com instead of ,ca
Your ID page says you are located in Canada. Is ebay.ca the listing site in which you created the listings?
Their listings are in $US and created on .com