If an opportunity that you've been invited to bid on doesn't appear on Bonfire, it may be a Private project.
Private Projects are a controlled-access Project, controlled by providing a Private Link (sometimes called an encrypted link) to access the Project directly instead of the using the portal or an email invite.
Each time you wish to access the Private Project, you'll need to use the link as there is no direct association between your account and the Project. The link should look something like this:
If you do not recall receiving this link, please contact the bid administrator as they are the only one with the authority to send this link out.
If you've received a link but it doesn't appear to lead anywhere, please see Why can't I access a Private Project when I click on the link?