Unsolvable how?
If you immediately get another Captcha even though you are solving it correctly, try a different browser to rule out a browser issue. Blocking cookies (or third-party cookies) can cause Captcha issues. Try disabling add-ons such as ad blockers that might interfere with Captcha.
Try going to ebay.com and signing in there rather than using an old bookmark that may not be redirecting properly.
