What is the name of the domain?
What is the error message?
無法連線至伺服器，請重新檢查伺服器和通訊埠
May I ask if you are trying to use [email protected] for sending emails by configuring it in an email client such as Microsofft Outlook or Mozilla Thunderbird? 
Cloudflare free Email Forwarding feature allows you to create personalized email addresses for your domain name and forward emails to other email addresses of your choice. It is an email forwarding service that does not allow creating fully-featured email accounts and send outgoing emails from [email protected] , since it’s a virtual email address.
You may consider some 3rd-party Email service provider, which allows creating such an email account to send e-mails within your domain name [email protected] .
Here’s how to get started: