I am a KMail user. Like every KDE software it also comes with a great many modification options. One of those settings is an email authentication type. You will hardly find any email service advertising their authentication type. I asked Zoho support what authentication type they support and I believe before I lose it, it needs to go on the web.
IMAP:- Plain
SMTP:- Plain or Login
I hope someone finds these useful.
Sudhir Khanger 