What happens when you try to sign in?
Is the problem with this eBay account or another one?
If you are using an old bookmark, try going directly to the main ebay.com page and sign in there instead.
Some other things to try:
Try another browser or the eBay app. Preferably the latest version of a popular browser. If you are using popup blockers, script blockers or tracking protection, try disabling those on the sign-in or verification page.
If you are using a VPN, try disabling that.
If you are using privacy software like Disconnect or Ghostery, try disabling those as well.
