Q: Are the emails in the email queue or not?
A: I tried with email queue enabled and disabled, exactly same behavior.
Q: Have you checked your email server logs?
A: I'm new to kentico, don't know where to find them.
Q: Also are there any errors in the Event log?
A: Nothing related to Emails, only http request errors.
Q: What is the version and hotfix you are using?
A: I don't know. CMS.Base is at v. 184.108.40.206
Q: How do you know it doesn't (especially locally)?
A: Because I tested it, I created @hotmail @outlook @gmail accounts and send email to my self.
Q: Are you getting some errors?
A: Nothing. No error occurs when sending the email.