Zoho Mail - issues with IMAP in Outlook and Sending Error issues

Zoho Mail - issues with IMAP in Outlook and Sending Error issues

Hi I have set up my zoho emai account in Outlook 2011,

And today have been receiving regular errors stating:

"connection to the server failed or was dropped"
"Mail could not be sent"
"error code 3259"

Attached is a screen shot of the error messages and also my account settings.

I am wondering is this an Outlook issue or a Zoho issue.

Please clarify asap, as I have been having many issues with this email account.