RDS MS SQL dbmail - limited to AWS SES only???

Hello, can I use my own SMTP server to send emails? I configured DB mail and created profile and account per https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/SQLServer.DBMail.html, but using my SMTP server (Amazon Linux instance, same VPC as RDS instance), but when I try sending an email I get 'profile name is not valid'. So am I forced to use Amazon Simple Email Service only? Thanks