The standard port used for SMTP connection is 25. Most often the reason for refused SMTP connection is that your Internet service provider blocks this port. That's why we recommend using the alternative port 2525 for your email SMTP connection.

For more information on how to check whether your ISP is blocking port 25, you can refer to this article.

Information on how to change the SMTP port for the most popular mail clients can be found in our Email tutorial.