This article will assist you with setting up Apple Mail, using IMAP, for your Hosted Mailbox. This article assumes you have macOS 10.12 (Sierra) or higher. To check your version, click on the Apple icon on the top left corner and then About this Mac.
1 – Launch Mail. If Mail is not in your dock, Command (⌘) + Space Bar. Then type Mail in the Spotlight search. Press enter to launch the Mail application., Within Mail, click Mail on the top left. Then select Add Account

2 – In the pop-up window, select Other Mail Account

3 – In the next screen, enter the following information:

Name: Enter your first and last name
Email Address: Enter your email address
Password: Enter your mailbox password

4 – Select Sign In. You will see an alert which says Unable to verify account name or password. Along with this alert, you will see more fields that require additional info

Fill in the following details:
Email Address: your email address
User Name: Your email Address (even though it says automatic, fill it in as shown)
Password: Your mailbox password
Account Type: IMAP
Incoming Mail Server: secure.emailsrvr.com
Outgoing Mail Server: secure.emailsrvr.com
Then click Sign In

Important Note: Apple Mail will usually clear the User Name field after entering the Incoming and Outgoing Mail Server fields. Ensure your User Name is filled in with your email address after entering the server information and before clicking Sign in

5 – Select the desired syncing options. You can leave the defaults on.

Next, we will configure your Mac to sync your various IMAP folders and prevent duplicate folders from showing up. We call this Folder Mapping; below are the steps to do so

6 – Within Mail, click Mail on the top left. Then select Preferences

7 – Select the Accounts tab at the top of the window, then select your IMAP email account from the left pane.

8 – Select the Mailbox Behaviors tab

9 – Click the Sent Mailbox dropdown and select the folder Sent that’s listed under your email address (not the folder listed under “On My Mac”)

10 – Click the Junk Mailbox dropdown and select the folder spam that’s listed under your email address (not the folder listed under On My Mac)

11 – Select close

Lastly, we will make sure our SMTP server settings are correct, as Apple Mail tends to change them automatically during setup

12 – While still on the Accounts screen, click on the Server Settings tab, next to Mailbox Behaviors

13 – Under Outgoing Mail Server SMTP, Uncheck the automatically manage connection settings. (Make sure you do it under SMTP, and not IMAP, as they have the same checkbox) This will unlock a new area below

14 – Go ahead and change the Port Number to 465, Click the Save button on the bottom right and Close the Accounts window.

15 – Finally, go back to the Mail app. Your email should begin downloading shortly, if it hasn’t already. Please wait 15 minutes for mail to download before troubleshooting any issues.