In hosting:
Try to enter your host :
performa460.com
SMtP/IMAP SSL - use don't use on SMTP and IMAP SSL default (for right now!)
Also do you have Webmail checked in SA/Web/Sites/performa460.com/web Services:
You need to have that checked . I took the liberty and went to your site try to access webmail. But I couldn't. All though this is not necessary it still helps to troubleshoot.
Let me know if you can log in to your mailbox web based after the changes have been applied.
You should reach it at
http://www.performa460.com/webmail
Csaba