Can't access webmail

I have 4 sites on one of your severs. I am unable to access my email via a 3 party program. This issue is only happening for one site. I have used this method so that I can check multiple emails on one program.

I am getting the following error:

Send Mail: Error verifying 'To’
Server Returned: 5.7.1 <MY IP ADDRESS>: Client host rejected: Access denied (#554)

I am on homiemail-sub4 so its not down…

I’d suggest submitting a support ticket via the panel ( with the specific email address you’re having trouble with, as well as the details you provided here. Our support team can look into it for you. Thanks!