ORA-12012: error on auto execute of job 425
ORA-29278: SMTP transient error: 421 Service not available
ORA-06512: at "SYS.UTL_SMTP", line 21
ORA-06512: at "SYS.UTL_SMTP", line 97
ORA-06512: at "SYS.UTL_SMTP", line 399
ORA-06512: at "TETS.HANDLER", line 208
ORA-29278: SMTP transient error: 421 Service not available
ORA-06512: at "SYS.UTL_SMTP", line 21
ORA-06512: at "SYS.UTL_SMTP", line 97
ORA-06512: at "SYS.UTL_SMTP", line 399
ORA-06512: at "TEST.EMAIL", line 1287
ORA-29278: SMTP transient error: 421 Service not available
ORA-06512: at line 1

SELECT a.job,a.what
FROM  dba_jobs a

Output is
------------
JOB WHAT
425  handler.StatusMail();

ORA-29278: SMTP transient error: %s
 *Cause:  A SMTP transient error occurred.
 *Action: Correct the error and retry the SMTP operation.