Oracle Error Message
ORA-01539: tablespace ‘string’ is not online
Reason for the Error
Failed to either make a tablespace read-only or offline because it is not online. A tblespace must be online before it can become read-only or offline normal.
Solution
Check the status of the tablespace. Use IMMEDIATE or TEMPORARY options to force all files offline. Bring the tablespace online before making it read-only.