HRESULT 0x80090367 (SEC_E_APPLICATION_PROTOCOL

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Description:

No common application protocol exists between the client and the server. Application protocol negotiation failed.

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SEC_E_ONLY_HTTPS_ALLOWED	SEC_E_INVALID_UPN_NAME

SEC_E_APPLICATION_PROTOCOL_MISMATCH

SEC_E_APPLICATION_PROTOCOL_MISMATCH means that the TLS peers could not select a common application protocol. In practice this is commonly an ALPN negotiation failure, for example when one side requires a protocol identifier that the other side does not offer.

What ALPN decides

ALPN lets the peers agree during the TLS handshake which application protocol will run inside the protected connection. It is separate from the TLS version and cipher suite; a successful TLS transport still needs a mutually supported application protocol.

What to check

Log the protocol identifiers offered by the client and accepted by the server.
Confirm that a proxy or TLS terminator is not changing the supported-protocol policy.
Do not send an application protocol the peer did not negotiate.

IETF: RFC 7301, ALPN · Microsoft: InitializeSecurityContext (Schannel)

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