Answered: Cannot connect and ECONNREFUSED error message

FTP server at ftp.adrive.com resolves into multiple addresses:

c:\>nslookup ftp.adrive.com
Server:  triton.hq.rebex.cz
Address:  192.168.2.3

Non-authoritative answer:
Name:    ftp.adrive.com
Addresses:  65.49.56.55
          65.49.56.53
          65.49.56.57
          65.49.56.56
          65.49.56.54
          65.49.56.52
          65.49.56.58

Rebex FTP/SSL uses the first address in the list. The order of resolved addresses is different each time, but the result is cached, which means Rebex FTP/SSL actually uses the same address each time until the cached DNS record expires.

We will consider changing this behavior (which means Rebex FTP/SSL would behave like FileZilla). In the meantime, use the following Resolve method as a workaround. Simply call serverName = Resolve(serverName) before calling Ftp.Connect method:

public static string Resolve(string serverName)
{
    // resolve server name
    IPHostEntry entry = Dns.GetHostEntry(serverName);

    // get all IPv4 addresses
    var addresses = new List<string>();
    foreach (IPAddress address in entry.AddressList)
    {
        if (address.AddressFamily == AddressFamily.InterNetwork)
            addresses.Add(address.ToString());
    }

    // if none found, get IPv6 addresses instead
    if (addresses.Count == 0)
    {
        foreach (IPAddress address in entry.AddressList)
        {
            if (address.AddressFamily == AddressFamily.InterNetworkV6)
                addresses.Add(address.ToString());
        }
    }

    // pick one of the addresses randomly
    if (addresses.Count > 0)
    {
        serverName = addresses[new Random().Next(0, addresses.Count - 1)];
    }

    return serverName;
}