SMTP永久性错误：550 5.7.1无法中继

Question

有人可以解决这个错误：

create or replace procedure email
as
begin
utl_mail.send(sender => 'abc@gmail.com',
recipients => 'xyz@gmail.com',
subject    => 'Test utl_mail.send procedure',
message    => 'test!');
end;
/

创建了程序。

execute email;
BEGIN email; END;

*
ERROR at line 1:
ORA-29279: SMTP permanent error: 550 5.7.1 Unable to relay
ORA-06512: at "SYS.UTL_SMTP", line 21
ORA-06512: at "SYS.UTL_SMTP", line 99
ORA-06512: at "SYS.UTL_SMTP", line 241
ORA-06512: at "SYS.UTL_MAIL", line 424
ORA-06512: at "SYS.UTL_MAIL", line 594
ORA-06512: at "SYS.EMAIL", line 4
ORA-06512: at line 1

我之前使用utl_mail配置了数据库。