C++ and Curl: Failed to receive handshake, need more data

I am trying to access a FTP using credentials.

I have never used curl and have limited understanding of what I'm doing, although I did research a lot of the functions I used. I have once developped a working FTP client and server in C, but it was unix only and a while ago, so it's mostly a curl problem to me (I really want to use curl as this has to be cross platform and I don't feel like wrapping everything myself besides I'm certain I'll have to know how to use curl eventually.)

The code so far (header file not included but I really doubt it's needed, password and login hidden for obvious reasons. They work, tested in filezilla)

    bool FTPClient::DownloadFile()
    {
CURL *curl;
CURLcode res;
char buffer[CURL_ERROR_SIZE + 1] = {};
struct FtpFile ftpfile =
{
    "test",
    NULL
};


curl_global_init(CURL_GLOBAL_DEFAULT);

curl = curl_easy_init();
if (curl) 
{

    curl_easy_setopt(curl, CURLOPT_URL,
        "https://[login]:[password]@lifesanctuary.eu/Update");
    curl_easy_setopt(curl, CURLOPT_PORT, 21);
    curl_easy_setopt(curl, CURLOPT_SSL_CIPHER_LIST, "TLSv1");
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, my_fwrite);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &ftpfile);
    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
    curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, buffer);
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);

    if (CURLE_OK != res) 
    {
        //ERREUR
        fprintf(stderr, "erreur CURL %d:\n%s\n", res, buffer);
        curl_global_cleanup();
        return false;
    }
}

if (ftpfile.stream)
    fclose(ftpfile.stream);

curl_global_cleanup();

return true;
    }

Output:

    *   Trying 91.121.145.87...
    * TCP_NODELAY set
    * Connected to lifesanctuary.eu (91.121.145.87) port 21 (#0)
    * schannel: SSL/TLS connection with lifesanctuary.eu port 21 (step 1/3)
    * schannel: checking server certificate revocation
    * schannel: sending initial handshake data: sending 185 bytes...
    * schannel: sent initial handshake data: sent 185 bytes
    * schannel: SSL/TLS connection with lifesanctuary.eu port 21 (step 2/3)
    * schannel: failed to receive handshake, need more data
    * schannel: SSL/TLS connection with lifesanctuary.eu port 21 (step 2/3)
    * schannel: encrypted data got 53
    * schannel: encrypted data buffer: offset 53 length 4096
    * schannel: next InitializeSecurityContext failed: SEC_E_INVALID_TOKEN (0x80090308) - Le jeton fourni Ó la fonction nÆest pas valide
    * Closing connection 0
    * schannel: shutting down SSL/TLS connection with lifesanctuary.eu port 21
    * schannel: clear security context handle
    erreur CURL 35:
    schannel: next InitializeSecurityContext failed: SEC_E_INVALID_TOKEN (0x80090308) - Le jeton fourni Ó la fonction nÆest pas valide

I don't know what the problem is. I have leads, searched up a bit and came to the conclusion that I either found things that were unrelated, or that I simply didn't understand.

For one it might be because of the encryption, SSL/TLS - I'm not very knowledgeable in that domain, the person who set up the server told me it used TLS, hence why I put that line:

    curl_easy_setopt(curl, CURLOPT_SSL_CIPHER_LIST, "TLSv1");

But I got no real idea how else to do it and it seems "TLSv1" was the only parameter I thought could fit in my context. I suspect it might be the problem.

Also, another problem I believe could be certificate related. I'm not entirely sure why but I'm sure that I didn't handle anything certificate related, and I'm not exactly sure what they are either. I know that I get to accept it when I log into my ftp with filezilla, but here I obviously don't.

So what is going on? Certificate problem? Encryption problem? Maybe something completely different? Thanks in advance.

EDIT: - I am assuming it is a certificate problem because to my knowledge anything https needs one and I don't handle anything on that regard, - I am considering it may be an encryption problem because this error code mostly seems to be caused by that - I don't know for sure at all it might very well be something else!

I think a series of misinformations from the person handing this server are in cause. I was told multiple times to use "https://" while it seems obvious that "ftp://" should be used and now I get a different error that seems to indicate I should not be using the encryption system he said I should use. I am closing this question as it sounds more of a problem from the team rather than from the code.