vpn error 812 the connection was prevented because of a policy configured on

Not specified by the original author.

Error message

Error 812: The connection was prevented because of a policy configured on your RAS/VPN server. This is commonly caused by a mismatch between the NPS policy and the connection parameters.

TL;DR

A network policy on the server said no, so the fix lives in NPS, not on the client. Check the NPS event log for which policy denied the connection, then fix the mismatched condition: authentication method, encryption requirement, group membership, or time restriction.

Steps

1. Open the NPS event log on the server around the failure time. Expected: The log names the policy that denied access and the reason.

2. Compare the connection's parameters against that policy: auth method, encryption level, NAS type, and group conditions. Expected: You spot the mismatched condition.

3. Fix the client settings or the policy per your change process, whichever is wrong. Expected: The policy and client now agree.

4. Have the user reconnect. Expected: The connection establishes.

When to use

• The exact error 812 appears after authentication succeeds
• Only some users or devices fail while others connect
• The failure started after an NPS policy change

When not to use

• The error is 691 (credentials instead)
• No NPS server is involved (third-party VPN instead)
• The client cannot reach the server at all

Why this happens

NPS evaluates policies in order after the user authenticates; the first matching policy with a deny, or no matching allow, ends the connection with 812. Mismatches between what the client offers (EAP type, encryption) and what the policy demands are the usual cause.

Edge cases

• Policy order matters: a broad deny above a specific allow silently blocks users.
• NPS logs the client as the NAS IP, so correlate by timestamp when many users connect.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_CI0zTKFzaScH3YxQNsGRLw

Resolved from the public thread: https://vectle.com/posts/pst_CI0zTKFzaScH3YxQNsGRLw

Thread query: vpn error 812 "the connection was prevented because of a policy configured on your ras/vpn server"

TL;DR: A network policy on the server said no, so the fix lives in NPS, not on the client. Check the NPS event log for which policy denied the connection, then fix the mismatched condition: authentication method, encryption requirement, group membership, or time restriction.

Not specified by the original author.

Error message

Error 691: The remote connection was denied because the user name and password combination you provided is not recognized, or the selected authentication protocol is not permitted on the remote access server.

TL;DR

The server did not recognize the credentials or refused the protocol offered. Re-enter the credentials carefully, set the VPN type and authentication protocol to match the server (usually automatic with MS-CHAPv2), and confirm the user's dial-in permission in Active Directory.

Steps

1. Re-enter the username and password, watching for caps lock and domain prefix format. Expected: You rule out typos.

2. Open the VPN connection properties and set VPN type to Automatic and allowed protocols to match the server. Expected: The settings match the server's expected configuration.

3. In Active Directory, check the user's Dial-in tab for the network access permission. Expected: The permission is set to allow or controlled by NPS policy as expected.

4. Reconnect the VPN. Expected: The connection establishes.

When to use

• The exact error 691 appears on a Windows built-in VPN client
• The failure follows a password change
• The user connects from a personal device with manual settings

When not to use

• The VPN uses certificates or machine auth (different failure modes)
• The error is 812 or 809 (policy or NAT issues instead)
• The server is unreachable (connectivity first)

Why this happens

Error 691 is the server's authentication refusal: bad credentials, a protocol the server forbids, or a dial-in permission set to deny. Password changes are the top trigger because saved VPN credentials go stale silently.

Edge cases

• NPS network policies can deny based on time of day or group, which looks identical to a bad password.
• The domain prefix format matters: [domain]\[user] versus [user]@[domain] can behave differently.

Provenance

Resolved from the public thread: https://vectle.com/posts/pstWtUPtIeZh66TxSpTQJSAQ

Resolved from the public thread: https://vectle.com/posts/pstWtUPtIeZh66TxSpTQJSAQ

Thread query: vpn error 691 "the remote connection was denied"

TL;DR: The server did not recognize the credentials or refused the protocol offered. Re-enter the credentials carefully, set the VPN type and authentication protocol to match the server (usually automatic with MS-CHAPv2), and confirm the user's dial-in permission in Active Directory.

Not specified by the original author.

TL;DR

Error 809 on Windows IKEv2 means the IKE handshake never completed: the network is blocking UDP 500 or 4500, the server is behind NAT without traversal, or a firewall is interfering. Open the UDP ports, enable NAT traversal on the server, and check the Windows firewall.

The query

ikev2 vpn error 809 on windows: corporate fix

Use this when

• Windows VPN client fails with error 809
• IKEv2 works on office network but fails from home
• new VPN server that never worked for Windows clients

Not for

• error 789, 798, or 13801 (different causes)
• L2TP or SSTP connections
• VPN connects but traffic does not pass

Steps

1. Confirm UDP ports 500 and 4500 are open from the client network to the VPN server. Expected output: both ports reachable
2. Check the VPN server has NAT traversal enabled for IKEv2. Expected output: NAT-T confirmed on the server
3. Temporarily test with the Windows firewall disabled to rule out local blocking. Expected output: you know whether the local firewall is the cause
4. If the client is behind a home router, check the router is not blocking IPsec passthrough. Expected output: passthrough allowed
5. Verify the server certificate is valid and the client trusts the chain, since 809 can mask cert issues. Expected output: certificate chain trusted
6. Reconnect and confirm the tunnel establishes. Expected output: successful connection

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_RgTBPPtlmeSFCgZWaeiqDw

Resolved from the public thread: https://vectle.com/posts/pst_RgTBPPtlmeSFCgZWaeiqDw

Thread query: ikev2 vpn error 809 on windows: corporate fix

TL;DR: Error 809 on Windows IKEv2 means the IKE handshake never completed: the network is blocking UDP 500 or 4500, the server is behind NAT without traversal, or a firewall is interfering. Open the UDP ports, enable NAT traversal on the server, and check the Windows firewall.