Oracle Solution for Error ora-30026

ORA-30026: Undo tablespace 'string

' has unexpired undo with string

(sec) left, Undo_Retention=string

(sec)

What triggered the Error:

Tried to drop a tablespace that contains unexpired undo information

What should we do to fix it:

lower setting of UNDO_RETENTION or wait a while before reissue command to drop undo tablespace