C++ WinSock sending files - c++

Question

Recently, i've been assigned a client/server project, which is basically a chat room, where files can be sent and recieved, and we can use webcams.
I'm currently working on the file transfer part, and after looking at some online tutorials, i've noticed most of them use offsets to write into their buffers, then they write the whole buffer into their new file.
To replicate that kind of code, i've set up 2 buffers, one on the client side, the other on the server side. On the server side, i read 8192 bytes from my file, into the buffer, then i send it into the client side, which recieves it, and adds it to my buffer. Problem is, after the second file transfer, every single transfer it does, it's a SOCKET_ERROR, which probably means something's not quite right.
server:
std::ifstream readFile;
readFile.open(FileName, std::ios::binary | std::ios::ate);
if (!readFile)
{
std::cout << "unable to open file" << std::endl;
}
int FileSize = readFile.tellg();
readFile.seekg(0);
int remainingBytes = 0;
uint32_t FileSize32t = (uint32_t)FileSize;
FileSize32t = htonl(FileSize32t);
send(connections[ID], (char*)&FileSize32t, sizeof(uint32_t), 0);
int sent_bytes = 0;
int offset = 0;
char data[8192];
remainingBytes = FileSize;
int i = 0;
while (i<6)
{
readFile.read(data, 8192);
if (remainingBytes < 8192)
{
sent_bytes = send(connections[ID], data+offset, remainingBytes, 0);
remainingBytes -= sent_bytes;
offset += sent_bytes;
}
else
{
sent_bytes = send(connections[ID], data+offset, 8192, 0);
if (sent_bytes == SOCKET_ERROR)
{
std::cout << "erro" << std::endl;
}
remainingBytes -= sent_bytes;
offset += sent_bytes;
std::cout <<"offset: "<< offset << std::endl;
std::cout << "Sent bytes: " << sent_bytes << std::endl;
std::cout << "remaining bytes: " << remainingBytes << std::endl;
}
i++;
}
Client:
char data[8192];
std::ofstream writeFile;
writeFile.open("Putin.jpg", std::ios::binary);
int bytesReceieved = 0;
int totalBytesReceieved = 0;
int i = 0;
while (i<6)
{
if (recvFileSize - totalBytesReceieved < 8192)
{
bytesReceieved = recv(connection, data+totalBytesReceieved, recvFileSize - totalBytesReceieved, 0);
totalBytesReceieved += bytesReceieved;
}
else
{
bytesReceieved = recv(connection, data + totalBytesReceieved, 8192, 0);
totalBytesReceieved += bytesReceieved;
std::cout << totalBytesReceieved << std::endl;
}
i++;
}
writeFile.write(data, totalBytesReceieved);
std::cout << "transferência terminada, bytes recebidos: " << totalBytesReceieved << std::endl;
writeFile.close();
Do note that this is just a test program, and it's preety much one of my first interactions with C++. I've been told this probably isn't the best way to start off with C++, but i need this assignment done until the 15th of september, so i need to finish it regardless. If you find any errors or problems besides my original issue do feel free to point them out and if you can, explain me why it's wrong.
Thank you very much for your help.