POP Peeper FAQ
Server Settings
Yahoo: IMAP security (Oauth2) - Use the OAuth2 login method (recommended for improved security): Edit your account in POP Peeper; press the 'OAuth2' button and follow the instructions
- Disable OAuth2: Use the following URL to disable OAuth2 in your Yahoo account:
https://login.yahoo.com/account/security
Enable: "Allow apps that use less secure sign in"
Yahoo has started blocking normal login methods for IMAP/SMTP -- first reported around June 2016 -- in favor of using the OAuth2 login method.
Yahoo will report an error of:
([AUTHENTICATIONFAILED] #MBR1212 Incorrect username or password.)