The Schannel error ‘The following fatal alert was generated: 10’ is a common issue in Windows systems, often related to TLS/SSL communication failures. This error occurs when the Secure Channel (Schannel) security package encounters a problem during the handshake process between a client and server.
The fatal alert code 10 specifically indicates an unexpected message or protocol violation, which can stem from outdated certificates, misconfigured TLS/SSL settings, or incorrect system date and time. Resolving this error requires a systematic approach to ensure secure communication channels are properly established.
Update Certificates to Resolve Schannel Error
Certificates play a critical role in TLS/SSL communication. If the certificates on your system are expired, invalid, or mismatched, the Schannel error is likely to occur. Begin by checking the validity of the certificates installed on your system. Open the Microsoft Management Console (MMC) and add the Certificates snap-in for the local computer. Navigate to the Personal and Trusted Root Certification Authorities folders to inspect the certificates.
- Ensure the certificates are not expired or revoked.
- Verify that the certificate chain is complete and trusted.
- Replace any outdated or invalid certificates with updated ones from a trusted Certificate Authority (CA).
If you are using self-signed certificates, ensure they are properly configured and trusted by the system. Misconfigured self-signed certificates can trigger the fatal alert error.
Verify TLS/SSL Protocol Settings
Incorrect TLS/SSL protocol settings can lead to communication failures. Windows systems use the Schannel security package to handle TLS/SSL protocols, and misconfigurations can result in fatal alert errors. To verify and adjust these settings, access the Group Policy Editor (gpedit.msc) or the Registry Editor (regedit.exe).
- Navigate to Computer Configuration > Administrative Templates > Network > SSL Configuration Settings in the Group Policy Editor.
- Ensure that the appropriate TLS/SSL protocols (e.g., TLS 1.2) are enabled.
- Disable outdated protocols like SSL 2.0 and SSL 3.0, as they are no longer secure.
If you are using the Registry Editor, locate the Schannel key under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL. Verify that the protocol settings align with your security requirements.
Ensure Correct System Date and Time
An incorrect system date or time can cause certificate validation to fail, leading to the Schannel error. Certificates rely on accurate timestamps to determine their validity. If your system clock is out of sync, the certificates may appear expired or invalid, even if they are not.
- Open the Date and Time settings in Windows.
- Enable Set time automatically to synchronize with an internet time server.
- Manually adjust the date and time if automatic synchronization is not available.
After correcting the system date and time, restart your computer and test the connection to see if the Schannel error persists.
Review Event Viewer Logs
The Windows Event Viewer provides detailed logs that can help diagnose the Schannel error. Open the Event Viewer and navigate to Windows Logs > System. Look for entries related to Schannel or TLS/SSL errors.
- Identify the source of the error and note any specific error codes or messages.
- Use the information from the logs to pinpoint the issue, such as a specific certificate or protocol failure.
Reviewing these logs can provide additional insights into the root cause of the fatal alert error.
Test the Connection After Resolving Issues
After implementing the above steps, test the connection to verify that the Schannel error has been resolved. Use tools like Ping, Telnet, or PowerShell to check the connectivity between the client and server.
- Run Test-NetConnection in PowerShell to test the connection to the server.
- Verify that the TLS/SSL handshake completes successfully.
If the error persists, revisit the steps to ensure all configurations are correct and up to date.