Additional Study Information: The purpose of this study is to find out the effects and safety of an investigational (experimental) new drug called copanlisib in pediatric patients from 6 months to 21 years of age. This study consists in two-phase, Phase I part will determine which is the right dose of copanlisib to be used in children/adolescents/adults with relapsed (has returned) or refractory (did not respond to standard treatment) solid tumor or lymphoma. Phase II part will further evaluate the effects and safety in pediatric patients with relapsed or refractory neuroblastoma, ostesarcoma, rhabdomyosarcoma and Ewing sarcoma. Patients will receive copanlisib intravenous (IV) infusion on Day 1, Day 8, and Day 15 of every 28-day treatment cycle. The study, Phase I and Phase II parts, is composed of the following periods: Screening; Treatment; Active follow-up; Long-term follow-up.