You see error 0x800CCC90 when Outlook cannot send or receive email from your POP3 account. This error means the mail server rejected your username and password. The problem is usually caused by incorrect account settings or a security policy on the server. This article provides the steps to resolve the login failure and get your email working again.
Key Takeaways: Fixing POP3 Login Error 0x800CCC90
- Account Settings > Server Settings: Verify your incoming and outgoing server names, port numbers, and encryption method match your email provider’s requirements.
- File > Account Settings > Change > More Settings > Outgoing Server: Enable the “My outgoing server requires authentication” option if your provider mandates it for POP3.
- Windows Security dialog: Re-enter your email password here if it has changed or was saved incorrectly, as this overrides the password in Account Settings.
Why Outlook Shows Error 0x800CCC90
Error 0x800CCC90 is a server authentication failure. Outlook sends your login credentials to your email provider’s POP3 and SMTP servers, but the servers deny the request. The most common reason is a mismatch between the settings in Outlook and the exact configuration required by your email service.
Modern email providers often enforce secure connections and specific authentication methods. If Outlook is configured for an older, less secure protocol like basic authentication over an unencrypted port, the server will block the login attempt. Another frequent cause is an expired or recently changed password that has not been updated in all the necessary locations within Outlook and Windows.
How Authentication Works for POP3 Accounts
For a POP3 account, authentication happens in two places. First, Outlook authenticates with the incoming POP3 server to download your messages. Second, it must authenticate with the outgoing SMTP server to send messages. Many providers require SMTP authentication even for POP3 accounts. If the “My outgoing server requires authentication” setting is off, the SMTP server will reject the send attempt, triggering the same error.
Steps to Correct Your POP3 Account Settings
Follow these steps in order to diagnose and fix the login problem. Start by checking your provider’s website for their current POP3 and SMTP server settings.
- Open Outlook Account Settings
Go to File > Account Settings > Account Settings. Select your POP3 email account from the list and click Change. - Verify User Information and Server Names
In the Change Account window, confirm your email address is spelled correctly. Check the Incoming mail server and Outgoing mail server fields. These are often something like pop.provider.com and smtp.provider.com. Do not rely on old information. - Click More Settings
Click the More Settings button in the lower-right corner of the Change Account window. A new dialog box will open. - Configure the Outgoing Server Tab
Click the Outgoing Server tab. Check the box for “My outgoing server requires authentication.” Usually, you will select “Use same settings as my incoming mail server.” Click OK. - Configure the Advanced Tab
Click the Advanced tab. Verify the port numbers. Standard secure ports are 995 for POP3 and 465 for SMTP, but some providers use 587 for SMTP. Ensure the encryption method is correct, typically SSL/TLS for both. Click OK. - Test the Account Settings
Back in the Change Account window, click Next. Outlook will test your account settings by attempting to log in. If it fails, a Windows Security dialog will appear. - Update Your Password in the Security Dialog
In the Windows Security dialog, carefully re-enter your current email account password. You may check “Remember my credentials” for convenience. Click OK to proceed with the test.
Alternative Method: Create a New Profile
If the error persists, corrupted profile data might be the cause. Create a new Outlook profile to start with fresh settings.
- Open Mail Setup
Close Outlook. Open the Windows Control Panel, view by Large icons, and select Mail (Microsoft Outlook). Click Show Profiles. - Add a New Profile
Click Add. Type a name for the new profile, like “Work Email,” and click OK. Follow the prompts to add your POP3 account with the correct settings from your provider. - Set the New Profile as Default
Back in the Mail dialog, select “Prompt for a profile to be used” if you have multiple accounts, or select your new profile and choose “Always use this profile.” Click Apply and OK, then restart Outlook.
If Outlook Still Shows Error 0x800CCC90
Antivirus or Firewall is Blocking the Connection
Security software can sometimes interfere with Outlook’s communication. Temporarily disable your antivirus or firewall email scanning feature and try sending/receiving again. If this fixes it, reconfigure the security software to allow Outlook or add an exception for its processes.
Email Provider Requires an App Password
If you have two-factor authentication enabled on your email account, you cannot use your regular password in Outlook. You must generate a unique app password from your email provider’s security settings. Use this 16-character code in place of your normal password in the Windows Security dialog.
Account is Temporarily Locked
Multiple failed login attempts can cause your provider to lock the account for a short period. Wait 15-30 minutes before trying again. You can also try logging into your email via the provider’s webmail interface to confirm your password is correct and unlock the account.
POP3 vs IMAP for Error Resolution
| Item | POP3 (Post Office Protocol) | IMAP (Internet Message Access Protocol) |
|---|---|---|
| Authentication Failure Impact | Blocks both sending and receiving | Can block sync but may allow cached access |
| Primary Settings Location | Outlook Account Settings & More Settings dialog | Outlook Account Settings |
| Key Setting for Sending | Outgoing Server (SMTP) authentication must be enabled separately | SMTP authentication is typically tied to IMAP login |
| Password Update Method | Windows Security dialog often overrides saved password | Password updated directly in Account Settings or via modern authentication prompt |
| Profile Corruption Fix | Often requires creating a new mail profile | Can sometimes be fixed by removing and re-adding the account |
You can now diagnose and fix the POP3 login error by verifying server settings and enabling SMTP authentication. For a more modern setup, consider switching your account to IMAP if your provider supports it. An advanced tip is to use the Test Account Settings feature in the More Settings dialog, which provides a detailed log to pinpoint the exact stage of the connection failure.