Unable to login in Kibana after enable x-pack

Hello Yang,

I try authenticate with the curl:

curl -u kibanaadmin:*** http://localhost:9200/_security/_authenticate

and the output was:

{"error":{"root_cause":[{"type":"security_exception","reason":"unable to authenticate user [kibanaadmin] for REST request [/_security/_authenticate]","header":{"WWW-Authenticate":"Basic realm=\"security\" charset=\"UTF-8\""}}],"type":"security_exception","reason":"unable to authenticate user [kibanaadmin] for REST request [/_security/_authenticate]","header":{"WWW-Authenticate":"Basic realm=\"security\" charset=\"UTF-8\""}},"status":401}

And I can't authenticate...

Thank you for your help.