How Do I Fix My SMTP Server?
How to troubleshoot sending email (SMTP) issues?
Open the settings for your email in the application or device you’re using, find the SMTP server and its settings, check the current outgoing port and change it to 26 or 587, make sure all username and password fields are filled in if displayed, save and test changes. In most email clients, the SMTP port, SSL settings, and SMTP authentication are updated on the same settings page, and this page is usually in the Advanced Settings option.