If your email provider isn't one of Newton's built-in choices, you can still add any mailbox that supports IMAP. You enter the incoming (IMAP) and outgoing (SMTP) server settings yourself; your provider's help pages list them.
Steps
Desktop
Click your avatar in the top-right corner and choose Add Account.
Choose IMAP (other).
Enter your Email address and Password. Display name (optional) is the name Newton shows for this account.
Under the server settings, enter the IMAP host, Port and Security for incoming mail.
Check Username. It's usually your email address.
Enter the SMTP host (outgoing mail), SMTP port and SMTP security.
Click Test connection. When it says Connected, click Connect.
iPhone, iPad & Android
Open the menu and tap the Settings gear at the bottom.
Tap Accounts › Add account › IMAP (iCloud, Yahoo…).
Tap Custom.
Enter your Email and Password.
Under INCOMING MAIL SERVER, enter the Host and Port. Fill in Username (if different from email) only if your provider asks for it.
Under SECURITY, choose SSL/TLS, STARTTLS or None.
Under OUTGOING MAIL SERVER, enter the Host and Port, then choose OUTGOING SECURITY.
Tap Add account. Newton checks the settings before adding the account, and says Could not connect if something's wrong.
Setting up Newton for the first time? Tap the IMAP tile. The same fields appear under Server settings.
Good to know
These are the usual ports. Make sure the port matches the security you choose:
Security
Incoming (IMAP)
Outgoing (SMTP)
SSL/TLS
993
465
STARTTLS
143
587
When you type the incoming server, Newton fills in a matching outgoing server, often by swapping imap. for smtp.. Check it against your provider's settings.
Avoid None for security if your provider offers SSL/TLS or STARTTLS. With None, your password and mail travel unencrypted.
IMAP accounts don't get filters, alias sync or team shared inboxes, and Newton stores the password encrypted on its servers so your other devices can connect.