[Troubleshooting] MailSendException: Could not send mails: 501 illegal character(s) in domain string

[Scenario]
As I wrote a Java code, and used JavaMail to send email. But it threw this kind of exception message:
org.springframework.mail.MailSendException: Could not send mails: 501 : illegal character(s) in domain string

[Solution]
Because the computer's host name is Big5, so it will throw this kind of exception. This problem had been resolved, as I change my host name to English, and restart my computer.