system error 1231
Moderate
Microsoft · Windows
Network location cannot be reached — the device or resource is on the network but Windows cannot establish a connection to it at the transport layer
Quick Answer
Error code System Error 1231 on your Microsoft Windows means: Network location cannot be reached — the device or resource is on the network but Windows cannot establish a connection to it at the transport layer. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
Likely Causes
How to Fix It
1
First confirm basic connectivity: ping the target machine by IP address
2
Check that both machines are on the same network profile type: Settings > Network & Internet > your connection — both should be set to 'Private'
3
On the target machine, temporarily disable Windows Firewall to test if it is blocking the connection: Windows Security > Firewall & network protection > turn off for Private network
4
If using IPv6, try disabling it temporarily: Network adapter properties > uncheck Internet Protocol Version 6 (TCP/IPv6)
5
Reset the network stack: open Command Prompt as Admin and run: netsh int ip reset then netsh winsock reset then restart
6
If using a VPN, disconnect it and test — VPNs can redirect traffic away from the local network
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
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