Can't add IMAP email to my account.

For classic Outlook on Windows, the message means the email provider may require an app password for that IMAP account. It is not a separate Microsoft app to install.

Use this process:

1. In classic Outlook, go to File > Add Account.
2. Enter the IMAP email address and continue.
3. If Outlook says “Please create an app password for Outlook on your email provider’s site”, go to the mail provider’s account security page and generate an app password there.
4. Copy that app password.
5. Return to Outlook and paste the app password when prompted for the account password.

Important details:

• The app password comes from the email provider for that mailbox, not from Outlook.
• It is used instead of the regular password when Outlook asks for the password.
• This is commonly required for some IMAP accounts.

If automatic setup still fails in classic Outlook, manual setup is available:

1. Go to File > Add Account.
2. Enter the email address.
3. Select Advanced options > Let me set up my account manually.
4. Choose POP or IMAP.
5. Enter the password. If the provider requires it, use the app password.
6. If setup fails, select Change Account Settings and enter the server settings provided by the email provider.

If the IMAP account is Yahoo in particular, classic Outlook now supports OAuth for Yahoo IMAP on supported update channels, so an app password is no longer needed there. In that case, sign in with the regular Yahoo password instead.

Also, if Outlook never prompts for a password during IMAP setup, on the IMAP details page make sure Require logon using Secure Password Authentication (SPA) is unchecked.

References:

• Add an email account to Outlook for Windows
• Troubleshoot Outlook email setup
• How to add a Yahoo IMAP account to Outlook Desktop without an App Password