Oracle® Database 11g / 12c / 18c error codes ORA-01548: active rollback segment '[string]' found, terminate dropping tablespace

ORA-01548: active rollback segment '[string]' found, terminate dropping tablespace

Oracle Error Code: ORA-01548

Cause: Tried to drop a tablespace that contains active rollback segment(s)

Action: Shutdown instances that use the active rollback segments in the tablespace and then drop the tablespace