After run a script for check my db tablespaces, the error log is SP2-0308: cannot close spool file, how to solve the problem?

+ + date +%Y%m%d
today=20170710
+ . /export/home/oracle/.profile
+ 1> /dev/null 2>& 1
+ sqlplus -s /as sysdba
+ 0<<

spool /export/home/oracle/logs/DDMSDB_tablespace_20170710.txt

col tablespace_name for a18
set pagesize 100
select a.tablespace_name tablespace_name,
nvl(ceil((1 - b.free / a.total) * 100),100) "usage_of_tablespace%",
nvl(b.free,0) "left_space(M)",
c.EXTENT_MANAGEMENT "Extent_management"
from (select tablespace_name, sum(nvl(bytes, 0)) / 1024 / 1024 total
from dba_data_files
group by tablespace_name) a,
(select tablespace_name, sum(nvl(bytes, 0)) / 1024 / 1024 free
from dba_free_space
group by tablespace_name) b,
dba_tablespaces c
where a.tablespace_name = c.tablespace_name
and c.tablespace_name = b.tablespace_name(+)
order by (1 - b.free / a.total) * 100 desc;

quit

TABLESPACE_NAME usage_of_tablespace% left_space(M) Extent_man
------------------ -------------------- ------------- ----------
UNDOTBS1 63 12945.0625 LOCAL
LARGE_BOSTON_INDEX 55 161280 LOCAL
LARGE_BOSTON 49 176896 LOCAL
BOSTON 46 4456 LOCAL
SYSAUX 35 670.3125 LOCAL
BOSTON_INDEX 23 20684 LOCAL
SYSTEM 22 803.773438 DICTIONARY

7 rows selected.

SP2-0308: cannot close spool file
+ mailx -s DDMSDB TABLESPACE STATISTICS wu_qi_yao@asmc.com.cn
+ 0< /export/home/oracle/logs/DDMSDB_tablespace_20170710.txt
+ mailx -s DDMSDB TABLESPACE STATISTICS xin_rong_wu@asmc.com.cn
+ 0< /export/home/oracle/logs/DDMSDB_tablespace_20170710.txt
+ mailx -s DDMSDB TABLESPACE STATISTICS dan_ji_zhan@asmc.com.cn
+ 0< /export/home/oracle/logs/DDMSDB_tablespace_20170710.txt
+ echo logout
logout