Oracle Network ACL

Get in contact with another Server – Access Control List (ACL)

https://joelkallman.blogspot.com/2010/10/application-express-network-acls-and.html

Enable Oracle database to send emails via SMTP server

Network ACLs and Database Upgrade to Oracle 12c

How to send mail from Oracle APEX

https://dbaclass.com/article/ora-24247-network-access-denied-by-access-control-list-acl/

Oracle 11g Acces Control List and ORA-24247

How to Send Emails from APEX to an External Source Using Gmail’s SMTP

http://dgielis.blogspot.com/2019/10/free-oracle-cloud-11-sending-emails.html