It seems like you are experiencing an issue with accessing the shared folder on your Windows Server 2012 from Windows 10 and 11 clients. The problem arises when the network type is not set correctly on the clients, resulting in a wrong username or password error when accessing the shared folder.
Here are a few troubleshooting steps you can try to resolve this issue:
1. Check Network Profile: Ensure that the network profile on your Windows 10 and 11 clients is set to Private. You can do this by going to Settings > Network & Internet > Status > Network and selecting the network connection. Set the profile to Private if it is currently set to Public.
2. Enable Network Discovery: On the server running Windows Server 2012, enable network discovery in the network settings. Open Control Panel, go to Network and Sharing Center, and click on Change advanced sharing settings. Make sure the network discovery option is turned on.
3. Check Firewall Settings: Verify that the firewall settings on both the server and client machines allow file and printer sharing. You can temporarily disable the firewall to see if it resolves the issue. If it does, you can then configure the firewall to allow the necessary ports and services for file sharing.
4. Check Share Permissions: Ensure that the shared folder on the server has the appropriate share permissions set for the client machines. Go to the properties of the shared folder, click on the Sharing tab, and check the permissions granted to the users or user groups. Make sure the client machines have the necessary permissions to access the folder.
5. Verify Credentials: Double-check the username and password being used to access the shared folder. If you're using different credentials on the client machines, make sure they are correct and match the ones set on the server.
6. Windows Credential Manager: If you have previously accessed the shared folder using different credentials, Windows might be caching the incorrect credentials. Open the Credential Manager on the client machines (Control Panel > Credential Manager) and remove any saved credentials related to the shared folder. Then try accessing the shared folder again.
7. Network Troubleshooter: Use the built-in network troubleshooter on the Windows 10 and 11 clients to diagnose and resolve any network-related issues. Right-click on the network icon in the system tray, select Troubleshoot problems, and follow the prompts.
If none of these steps resolve the issue, you might consider setting up a domain environment instead of a workgroup, as it can provide better control and management of network resources. Domain environments allow for centralized user and permission management, which can help simplify access to shared folders.
I hope these suggestions help you resolve the problem with accessing your shared folder. Let me know if you have any further questions or concerns!