createShareButton() not working

[rahulserver]

I am trying to create a share button like this:

                let buttons = [];
    buttons.push(botly.create());
    botly.sendButtons({
        id: senderId,
        text: "some text",
        buttons: buttons
    }, ((err, resp) => {
        console.log("Err: ", JSON.stringify(err));
        console.log("resp: ", JSON.stringify(resp));
    }));

But nothing shows up and on console.log shows this:

Err:  null
resp:  {"error":{"message":"(#100) Invalid button type","type":"OAuthException","code":100,"error_subcode":2018037,"fbtrace_id":"FhJ0FhIk6C2"}}