What does Windows error code 13802 (ERROR_IPSEC_IKE_ATTRIB_FAIL) mean?

ERROR_IPSEC_IKE_ATTRIB_FAIL

ERROR_IPSEC_IKE_ATTRIB_FAIL indicates that the peers authenticated but could not accept the negotiated IKE/IPsec attributes. The mismatch can be in identities, proposal parameters, lifetimes, traffic selectors, or another policy value.

Because authentication has already succeeded, begin with the negotiated policy attributes rather than credential replacement. A trace of the accepted proposal and the rejected attribute usually narrows the mismatch faster than repeating the connection attempt.

What to check

• Compare the effective connection-security rules and IPsec proposals on both sides, not just the intended GPO settings.
• Check whether a recent policy change introduced different authentication, encryption, integrity, or lifetime requirements.
• Capture the negotiation on both peers when the effective policies appear identical.

Get-NetIPsecMainModeSA
Get-NetIPsecQuickModeSA

Microsoft: Connection security rules

Microsoft: Get-NetIPsecMainModeSA

Microsoft: Use Netsh to manage network traces