Issues with email client authentication

[Stevecowie]

I'm trying to login to email using apple mail / desktop email client but i keep getting error message:  Can not authenticate to IMAP server: Access denied.

even though the username / password are correct. 

Works fine on my phone but not desktop. 

is BT restricting ip adresses? 

[licquorice]

Have you ticked the ' Authentication required' box in the client? Have you selected plain authentication rather than secure authentication?