- Plesk for Windows
Upon sending e-mail via Horde webmail, the following error appears in UI:
CONFIG_TEXT: There was an error sending your message: Could not open secure TLS connection to the server.
There is no certificate assigned for the mail server in MailEnableAdmin > Servers > localhost > Properties > SSL :
Certificate is required to establish TLS connection, but it is not set in MailEnable.
Navigate to Plesk > Tools & Settings > SSL/TLS Certificates ;
Click on [Change] link on the right of Certificate for securing mail :
Select a certificate, which will be assigned to the Mail Server and click on OK :