There are two main protocols for email applications.
1) POP3 (Post Office Protocol 3)
2) IMAP (Internet Message Access Protocol)
You can change your POP3 connection to IMAP connection via the steps below.
1. Back up mailboxes
Back up mailboxes is an important step as switching from POP3 to IMAP may cause email to be deleted.
Go to Outlook and select File>Open & Export>Import/Export.
Select Export to a file>Next.
Select mailboxes that you wish to backup and ensure to check the checkbox next to Include Subfolders. Click Next.
Click Browse and select a location on your computer to store the backup. Click Finish.
You can create an optional password to ensure your backed-up emails are secure. Click OK after setting the password. You may click Cancel to proceed without password.
2. Remove POP3 account from computer.
Once Step 1 is successful, proceed with deletion of POP account in Outlook and account in other devices. Select File>Info.
Go to Account Settings>Info. Click on arrow down and select Account Settings option.
Click on email account and click Remove to delete from Outlook.
A pop up will appear to inform you that all offline messages will be deleted. Click Yes to continue.
3. Set up IMAP account on computer.
Create new email account on computer using IMAP server details.
There are two ways to create new email account.
a) Click New... buttion in Account Settings.
b) Click File>Add Account
Select Manual setup or additional server types>Next to proceed.
Under Choose Your Account Type,select POP or IMAP>Next.
Enter IMAP server settings for email account.
a. Email address - FULL email address
b. Password - server email password
c. User Name - email account user name
d. Account Type - select IMAP from dropdown menu
e. Incoming Mail Server - mail.domain.com
f. Outgoing Mail Server (SMTP) - mail.domain.com
g. Logon information- enter email account user name and password.
Click More Settings.
Under Internet Email Settings, click on Advanced tab.
The Non SSL settings are as below.
SSL settings are as below:
As for Outgoing Server, check the box My outgoing server (SMTP) requires authentication.
Select Use same settings as my incoming mail server.
Click OK and Next.
Outlook will test email settings.
In the event the testing fails, retrace steps and ensure server and account details have been entered correctly.
Once test is completed, click Close and Finish.
4. Restore mailbox
To restore mailbox, choose File>Open&Export>Import/Export.
Select Import from another program or file>Next.
Under Import a File, select Outlook Data File (.pst)>Next.
Click on Browse to retrieve Outlook backup file. You may select one of the Options to configure how Outlook treats duplicate items. Click Next.