我的数据库中有Mailgun设置配置。所有我想要的Mailgun客户端密钥，用户名，和电子邮件应该从数据库中提取任何邮件去客户端。但我不能设置数据。from: mailgun_email,这部分也是我们从数据库中获取的。请帮助我如何设置数据。还有一件事，如果我在电子邮件文件之外调用配置文件，它会给我一个错误mongoose错误，这是我所理解的，即在数据库设置缓冲超时错误之前调用配置文件。

错误MongooseError: Operation configurations.findOne() buffering timed out after 10000ms

邮件文件

let mg;

const configuration = async () => {
    const res = await Configuration.findById({ _id: process.env.CONFIGURATION_ID });

    let key = res.mailgun_api_key;
    let username = res.mailgun_username;

    return mailgun.client({
        username,
        key,
    });
};

const successOnRegisterMail = (user_email, user_name) => {
    configuration();
    try {
        mg.messages
            .create("sandbox1f0bc2b687fc416cbd9bdf7a7d1bc24c.mailgun.org", {
                from: mailgun_email,
                to: [user_email],
                subject: "",
                text: "Congratulation you've been successfully registered.",
                html: `<p>Hello ${user_name}</p> <br /><br /> <p>Congratulation you've been successfully registered.</p><br /> Best Regards, <br /> Team Developers`,
            })
            .then((msg) => console.log(msg)) // log response data
            .catch((error) => console.log(error)); // log any error
    } catch (err) {
        console.log("Error from Mail: ", err);
    }
};