/* Oculta pelo ID */
#wpcp-error-message {
    display: none !important;
    visibility: hidden !important;
    opacity: 0 !important;
}

/* Oculta pela classe */
.msgmsg-box-wpcp.warning-wpcp.hideme {
    display: none !important;
    visibility: hidden !important;
    opacity: 0 !important;
}