Hi Vincent,
You must have a valid license (Business user) in order to access Business project (Paid project). Please contact your project admin to review if the project still exists (not deleted) and upgrade your account to have a valid license assigned to your account through "My Trimble Subscriptions". So that you can get access to the business project going forward.
More details about upgrade account - Trimble Connect Account Upgrade Process
Thanks,
Fern