rollback tablespace not enough

[stecal]

What is the storage parameter for the tablespace? Unlimited? Probably not.

ORA-01650: unable to extend rollback segment %s by %s in tablespace %s
Cause: Failed to allocate extent for the rollback segment in tablespace.
Action: Use the ALTER TABLESPACE ADD DATAFILE statement to add one or more files to the specified tablespace.

Error: ORA 1562 Text: failed to extend rollback segment (id = %s)
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Cause: Failure occurred when trying to extent rollback segment Action: This is normally followed by another error message that caused the failure. Shutdown, restart and then take appropriate action for the error the caused the failure. If starting up the system again doesn't solve the problem, it is possible that there is an active transaction in the rollback segment and the system can't roll it back for some reason(s). Check the trace file generated by the PMON process for more information.