[Help] Running Mu through custom Proxy, Getting DC after 1 min. Python/C#

I'm trying to develop a simple proxy on C# / Python for sniffing mu packets. I'm targeting 97d+99i version.The game runs for about 1 minute then the socket is forcefully closed by the server and i get a DC. If I use any famous proxy like SolidProxy 1.22 the game runs with no problems.

1. Socket1 is listening on 127.0.0.1:proxyPort
2. Main.exe (cracked) is launched via launcher to connect to 127.0.0.1:proxyPort
3. Socket2 is connecting to target server serverIp:55901 (bypass 44405)
4. Whenever a packet is coming from client -> proxy -> server or from server -> proxy -> clientthe proxy buffers the binary data, assembles the C1-C4 packets according to the length header and only after that sends the packets either to the client or to the server. (Warning! I do not decrypt the packets, i simply make sure they are assembled, logged, and proxied to destination)

What am I doing wrong?Ideas:

1. Maybe its because I bypass 44405? (not sure)
2. Maybe its because i don't decrypt/encrypt the packets (might be)
3. Maybe there is a special packet i need to send manually like a checksum after X minutes/packets? (not sure)

Facts:

1. Hence SolidProxy 1.22 works without any issues i'm sure the disconnect is not happening because of an AntiCheat.
2. The client connects and works for approximatively 1 minute then the connection is closed by server. There must be some sync issues.
3. I have implemented the proxy in C# and Python.
4. I have also implemented a version which doesn't alter the packets and simply resends the buffer it also works for approx 1 minute.

I would really appreciate some resources on the theoretical aspect. What am i missing? Thank you!