To update or verify the settings for an Apple Mail IMAP account on vmail01.peak.org, start by going into Preferences/Accounts and click on the account you want to update on the left, then Account Information in the right pane:

Description

What shows in the left pane listing the accounts.

Email Address

The primary email address associated with this mailbox --- what shows in the From address when you send mail.

Full Name

Also shown in the From address in outgoing mail, but this is a comment and not used by the mail system for anything

Incoming Mail Server

This should be set to vmail01.peak.org unless otherwise directed by Peak Support.

User Name

Your actual mailbox email address. Note that this may not be the email address you actually use, in particular, if you have a private domain address forwarded to one of the Peak owned domains. If you're not sure, our support people can clarify the situation for you.

Password

We recommend that you leave this blank and not have your password saved: it's more secure, as otherwise anyone with access to your box can read your email, and probably more importantly, entering your password every time helps you remember it.

Next, click on Server Settings for the Outgoing Mail Server:

Outgoing Mail Server

This should be set to vmail01.peak.org unless otherwise directed by Peak Support.

Server port

Identifies the outgoing mail service; it must be 587. Port 25 is the default, but is restricted, only allowing access from spam filter systems so that spammers can't bypass them.

An important part here is to make sure that Use Secure Sockets Layer is checked. This makes sure your password is protected when your mail program logs in to send mail, and is required by vmail01.

Authentication

This should be set to Password

User Name

Your actual mailbox email address. Note that this may not be the email address you actually use, in particular, if you have a private domain address forwarded to one of the Peak owned domains. If you're not sure, our support people can clarify the situation for you.

Password

We recommend that you leave this blank and not have your password saved: it's more secure, as otherwise anyone with access to your box can read your email, and probably more importantly, entering your password every time helps you remember it.

Click OK to return to the Accounts window, then click Advanced:

The key part is at the bottom: make sure Use SSL is checked. This secures the connection when fetching mail the same as the setting in the previous section secured the connection when sending mail. The Port needs to be 993 and Authentication needs to be set to Password as well. It's probably a good idea to check the "Automatically synchronize changed mailboxes", but the IMAP Path Prefix should be left blank.

That's pretty much it as far as the settings needed for talking to the Peak mail server are concerned!