You should use APEX_MAIL.PUSH_QUEUE witch is documented
SMTP gateway host name
SMTP gateway port number
Note that these parameter values are provided for backward compatibility, but their respective values are ignored. The SMTP gateway hostname and SMTP gateway port number are exclusively derived from values entered on the Manage Environment Settings when sending email.
v_connection := UTL_SMTP.OPEN_CONNECTION('mail.host.com',25);
UTL_SMTP.DATA(v_connection,'this is page number 26 in TOPMGT application with USER BY :APP_USER');
this code should working fine over the sys account.then you can follow email plug or own email send code!
What else I need to send mail and what should I ask DBA to provide me so that mail can be sent successfully.
Please give some idea.
The Instance Administrator would also need to ensure the instance email settings were setup properly.