When you start working in Portfoleon, you are granted with 28 days of trial. During this period you can use the full set of features, which corresponds to the Portfolio Management plan.
As soon as your trial is over, your plan is changed automatically to the more restricted Free Forever, which provides limited number of portfolios, boards, custom fields, and users. It also does not include resource management capabilities.
If you want to upgrade your billing plan, then navigate in Portfoleon to the organization settings.