I get an error "Unsuccessful authentication" on my Windows 2016 server with local and domain accounts

Hello Josh Reinmann,

Has your problem been solved? If it has, please hit Accept the answer to support me!! If it hasn't, please tell me more about your problem details.

Thank you so much!!

QQ.

Dear Josh Reinmann,

Thank you for reaching out regarding the “unsuccessful authentication” error you are encountering when attempting to log into your member servers. This issue is often related to domain trust, credential validation, or security policy mismatches between the domain controller and the member server. As a first step, please verify that the servers are correctly joined to the domain and that the secure channel with the domain controller is intact by running nltest /sc_verify:<domain> or Test-ComputerSecureChannel. Next, confirm that the time synchronization between the domain controller and the member servers is accurate, as Kerberos authentication requires clocks to be within five minutes. It is also important to check Group Policy settings, firewall rules, and ensure that the appropriate authentication protocols (Kerberos/NTLM) are enabled. If the issue persists, rejoining the server to the domain or resetting the computer account in Active Directory may resolve the problem.

If these troubleshooting steps help address the issue, I kindly ask that you mark this response as “Accept the answer”, so that other administrators facing similar errors can benefit from the guidance.

Thank you so much!!

Kind regards,

QQ.

To troubleshoot the "unsuccessful authentication" error on your Windows Server 2016, you can follow these steps:

1. Check User Credentials: Ensure that the username and password you are using are correct. If using a domain account, verify that the account is active and not locked out.
2. Verify Network Connectivity: Ensure that the server is connected to the network and can reach the domain controller if applicable.
3. Check Domain Controller Availability: If your server is part of a domain, make sure that the domain controller is online and functioning properly. You can use the command ping <DomainControllerName> to check connectivity.
4. Review Event Logs: Check the Event Viewer on the server for any error messages related to authentication. Look under Windows Logs > Security and System for relevant entries.
5. Group Policy Settings: Ensure that the Group Policy settings are not restricting logon rights. You can review the Group Policy settings related to user rights assignment. Check if the user is included in the Remote Desktop Users group if remote access is being used.
6. NTLM and Kerberos Authentication: If your environment uses NTLM or Kerberos, ensure that the necessary services are running. If the Domain Controller is down, clients may fail to authenticate.
7. Check Local Security Policies: Open the Local Security Policy (secpol.msc) and navigate to Local Policies > User Rights Assignment. Ensure that the user or group has the appropriate rights to log on locally or through Remote Desktop Services.
8. Restart Services: Sometimes, restarting the Netlogon service on the server can resolve authentication issues. You can do this via the Services management console or using the command net stop netlogon followed by net start netlogon.
9. Check Firewall Settings: Ensure that the firewall settings are not blocking authentication requests. You may need to allow specific ports used for authentication (like TCP 88 for Kerberos).
10. Update Group Policies: Run gpupdate /force to refresh Group Policy settings on the server.

If these steps do not resolve the issue, consider checking for any recent changes to the server or network configuration that may have affected authentication processes.