You need to reset your password for your Email Quarantine account.
1. Go to the login page you are assigned to.
https://eu.quarantine.symantec.com (EMEA Quarantine Portal)
https://us.quarantine.symantec.com (NAM Quarantine Portal)
2. Click on "Forgot your password?" located under the Password Box
3. Enter your email address for Username
4. Push the "Reset Password" button
5. Click on the link in the email that is sent to you to choose a new password
6. Login to the Quarantine portal with the new password
For more information about unlocking a Quarantine portal account please see the article: How to unlock an Email Quarantine Account