Hi,

The error message "encoding with 'idna' codec failed (UnicodeError: label too long)" typically occurs when the email server name or email address being used for the outgoing mail server has exceeded the maximum length allowed by the server.


To fix this issue, you can try the following steps:

1.Check the email server name or IP address being used for the outgoing mail server to ensure it is correct.
2.Check the email address being used for the outgoing mail server to ensure it is correct and does not exceed the maximum length allowed by the server.
3.Try using a different email server or email address for the outgoing mail server and see if the error persists.

If the error persists, you can refer to the blog and video tutorials on email configuration in Odoo 12 to troubleshoot the issue further:

The blog can be found at https://www.cybrosys.com/blog/email-configuration-in-odoo 

and the video tutorial can be found at https://www.youtube.com/watch?v=tXi4jtIN_io.

Regards