Solution:

• If you received an email invitation to participate in the session, go to your invitation and click on the link again.
  If you entered the session through a panel company website, you can retrieve your link using the History. To reach you browser's history, click Ctrl+H. Look at today's history and find a link containing the words 'invoke' or 'myinvoke'. Clicking the link, you will return to the login page of the session and you will be able to continue answering questions. The first question you will receive will be the last question you have answered. If it is an open ended question, you will NOT be able to answer it again.