"Authentication failed" error

This error means the mail server rejected your username or password. You may see SMTP error codes such as 535 5.7.8 (Authentication credentials invalid), 535 5.7.3 (Authentication unsuccessful), 534 5.7.9 (Application-specific password required), or 534 5.7.14 (Please log in via your web browser first).

Common causes:

• Using your regular account password instead of an App Password.
• An expired or revoked App Password.
• A typo in your email address or password.
• SMTP authentication not enabled on your account.
• Two-Factor Authentication (2FA) enabled without generating an App Password.

Provider-Specific Steps:

Gmail:

1. You must use an App Password, not your regular Google password.
2. Go to https://myaccount.google.com/apppasswords (2FA must be enabled first).
3. Generate a new App Password for 'Mail' and paste it into WarmySender.
4. Your username must be your full Gmail address (e.g., [email protected]).

Outlook / Microsoft 365:

1. Generate an App Password at https://account.live.com/proofs/AppPassword or via your M365 admin portal.
2. Ensure SMTP AUTH is enabled: In Microsoft 365 Admin Center, go to Users > Active Users > select the user > Mail tab > Manage email apps, and check 'Authenticated SMTP'.
3. Your username must be your full email address (e.g., [email protected] or [email protected]).
4. If you see error 534 5.7.14 or 'Please log in via your web browser', sign in to Outlook on the web first and complete any security prompts.

Hostinger:

1. Use your regular email password (not an App Password).
2. SMTP host must be smtp.hostinger.com (not mail.yourdomain.com).
3. Your username is your full email address (e.g., [email protected]).
4. If you recently changed your password, wait a few minutes for propagation.

Zoho:

1. If 2FA is enabled, generate an App Password at https://accounts.zoho.com/home#security/security_apppassword.
2. If 2FA is not enabled, your regular Zoho password should work.
3. Your username is your full email address.
4. SMTP host: smtp.zoho.com (or smtp.zoho.eu / smtp.zoho.in depending on your region).

Yahoo:

1. You must use an App Password. Go to https://login.yahoo.com/account/security and generate one under 'App Passwords'.
2. Your username is your full Yahoo email address.

Debugging Steps:

1. Verify your username is your full email address (e.g., [email protected]), not just the part before the @.
2. Re-generate a fresh App Password and paste it carefully — avoid trailing spaces.
3. Confirm the SMTP host and port match your provider's requirements (see Provider Setup Guides).
4. Log in to your email provider's web interface and check for any security alerts or prompts that need to be resolved.
5. If you recently enabled 2FA, any previously saved passwords are invalidated — generate a new App Password.
6. Try disabling and re-enabling SMTP access in your provider's settings.

Still Not Working?
• Check your provider's status page for outages.
• Try connecting from a different network (some corporate networks interfere with SMTP authentication).
• Contact your email provider's support team and confirm that SMTP access with third-party apps is allowed on your account.
• As a last resort, try a different email provider to isolate whether the issue is account-specific.

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