We experience again and again that development teams lack explicit quality requirements from customers or key stakeholders.
That leaves the quality goals implicit leading to a high risk of misunderstanding and dissatisfaction of all the people involved.
Our advice: Make explicit assumptions about appropriate quality goals, based on your knowledge and experience - take an educated guess.
Together with 2-3 team members, you could write down those assumptions as scenarios and discuss these educated guesses with your stakeholders. Such assumptions are always better than having no explicit quality requirements!