There’s no code, I’m using MyBb. It has a built-in configuration servers for SMTPs. I’ve entered all the details, but it doesn’t seem to even connect. Maybe it’s the provider? I could try searching for another one, no idea.
You can use outlook for business for free with a dev account, all is free. Also you can use your domain to send emails like ([email protected]). SMTP, IMAP etc are allowed. Full-fledged like the premium plan
Can you please share your configuration (except confidential details like usernames and passwords of course) and what you see when you try to setup a connection or send a message with it?