hope you're all doing well.
I'm trying to make a program that will send an email using Gmail.
I have this command that works perfectly from CMD, but I can't figure out how to make it work in the application.
This is the command: curl smtps://smtp.gmail.com:465 -v --mail-from "<sir@gmail.com>" --mail-rcpt "<mister@gmail.com>" --ssl -u sir@gmail.com:password -T "mail.txt" -k --anyauth
These are the contents of mail.txt:

From: "Sir" <sir@gmail.com>
To: "Mister" <mister@gmail.com>
Subject: This is a test

Hi,
I’m sending this mail with curl thru my gmail account.
Bye!

I followed this example on the cURL wesite
And this is what I got:

static const char* payload_text[] = {
"From:<sir@gmail.com>\n"
"To:<mister@gmail.com>\n"
"Subject : This is a test\n\r"

"Hi,\n"
"I’m sending this mail with curl thru my gmail account.\n"
"Bye!\n"
};

struct upload_status {
    int lines_read;
};
static size_t payload_source(void* ptr, size_t size, size_t nmemb, void* userp)
{
    struct upload_status* upload_ctx = (struct upload_status*)userp;
    const char* data;

    if ((size == 0) || (nmemb == 0) || ((size * nmemb) < 1)) {
        return 0;
    }

    data = payload_text[upload_ctx->lines_read];

    if (data) {
        size_t len = strlen(data);
        memcpy(ptr, data, len);
        upload_ctx->lines_read++;

        return len;
    }

    return 0;
}

int curl_send_email()
{
    CURL* curl;
    CURLcode res = CURLE_OK;
    struct curl_slist* recipients = NULL;
    struct upload_status upload_ctx = { 0 };

    curl = curl_easy_init();

    if (curl)
    {

        curl_easy_setopt(curl, CURLOPT_URL, "smtps://smtp.gmail.com:465");

        curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
        curl_easy_setopt(curl, CURLOPT_MAIL_FROM, "<sir@gmail.com>");

        recipients = curl_slist_append(recipients, "<mister@gmail.com>");
        curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);

        curl_easy_setopt(curl, CURLOPT_USE_SSL, 1L);

        curl_easy_setopt(curl, CURLOPT_USERNAME, "<sir@gmail.com>");
        curl_easy_setopt(curl, CURLOPT_PASSWORD, "password");

        curl_easy_setopt(curl, CURLOPT_READFUNCTION, payload_source);
        curl_easy_setopt(curl, CURLOPT_READDATA, &upload_ctx);
        curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);

        curl_easy_setopt(curl, CURLOPT_HTTPAUTH, (long)CURLAUTH_ANY);

        /* Send the message */
        res = curl_easy_perform(curl);

        /* Check for errors */
        if (res != CURLE_OK)
            fprintf(stderr, "curl_easy_perform() failed: %s\n",
                curl_easy_strerror(res));

        /* Free the list of recipients */
        curl_slist_free_all(recipients);
        curl_easy_cleanup(curl);
    }

    return (int)res;
}

int main()
{

   int message = curl_send_email();
   std::cout << message << std::endl;

   return 0;
}

But it doesn't works, it return a messaged that says "login failed", even though the username and password are right.
Can someone please tell me what I'm doing wrong?
Thanks in advance.