Failed to create session

[novakduc]

I have tried to connect to a PLC which established OPC UA server (security policy None), but I failed to create session with below log:
[2022-03-31T10:00:26Z INFO my_opcua] start my opcua client.
[2022-03-31T10:00:26Z WARN opcua_client::config] Endpoint config contains no endpoints
[2022-03-31T10:00:26Z INFO my_opcua] created client
[2022-03-31T10:00:26Z INFO my_opcua] created endpoint.
[2022-03-31T10:00:26Z INFO opcua_client::session::session] Connect
[2022-03-31T10:00:26Z INFO opcua_client::session::session] Security policy = None
[2022-03-31T10:00:26Z INFO opcua_client::session::session] Security mode = None
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] Making secure channel request
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] security_mode = None
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] security_policy = None
[2022-03-31T10:00:26Z INFO opcua_client::session::session] Connect was successful
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] Making secure channel request
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] security_mode = None
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] security_policy = None
[2022-03-31T10:00:26Z INFO opcua_client::comms::tcp_transport] WriteState has dropped
[2022-03-31T10:00:26Z INFO opcua_client::session::session] Session has dropped
[2022-03-31T10:00:26Z INFO opcua_client::comms::tcp_transport] TcpTransport has dropped
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] SessionState has dropped
[2022-03-31T10:00:26Z INFO opcua_client::comms::tcp_transport] ReadState has dropped
[2022-03-31T10:00:26Z INFO opcua_client::session::session] Connect
[2022-03-31T10:00:26Z INFO opcua_client::session::session] Security policy = None
[2022-03-31T10:00:26Z INFO opcua_client::session::session] Security mode = None
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] Making secure channel request
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] security_mode = None
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] security_policy = None
[2022-03-31T10:00:26Z INFO opcua_client::session::session] Connect was successful
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] Making secure channel request
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] security_mode = None
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] security_policy = None
[2022-03-31T10:00:26Z ERROR opcua_crypto::security_policy] Specified security policy uri "" is not recognized
[2022-03-31T10:00:26Z ERROR opcua_client::session::session] session:2 Can't support the security policy
[2022-03-31T10:00:26Z ERROR opcua_client::client] Got an error while creating the default session - BadSecurityPolicyRejected
[2022-03-31T10:00:26Z INFO opcua_client::session::session] Session has dropped
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] Making secure channel request
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] security_mode = None
[2022-03-31T10:00:26Z INFO opcua_client::session::session_state] security_policy = None
[2022-03-31T10:00:26Z INFO opcua_client::comms::tcp_transport] WriteState has dropped
[2022-03-31T10:00:27Z INFO opcua_client::comms::tcp_transport] TcpTransport has dropped
[2022-03-31T10:00:27Z INFO opcua_client::comms::tcp_transport] ReadState has dropped
[2022-03-31T10:00:27Z INFO opcua_client::session::session_state] SessionState has dropped
thread 'main' panicked at 'called Result::unwrap() on an Err value: IS_ERROR | BadUnexpectedError | BadResourceUnavailable | BadCommunicationError | BadTooManyOperations | BadDataTypeIdUnknown | BadCertificateTimeInvalid | BadCertificateIssuerTimeInvalid | BadNotImplemented | BadMonitoringModeInvalid | BadMonitoredItemFilterUnsupported | BadFilterNotAllowed | BadServerNameMissing | BadDiscoveryUrlMissing | BadSecurityModeRejected | BadSecurityPolicyRejected', src/main.rs:35:10

Please advise me a direction to go. Thank you!