I wondering if any one could assist with this.

My company is using Zimbra. My client is using Outlook to send email to us.

Every time when they send emails to us, there is a pop up window comes up asking "The server mail.XXX.net at Zimbra requires a username and password", and it doesn’t just come up once.. they have to hit cancle about 12 times before sending emails to us.. its really annoying.


Anyone could help me with this? Thanks