Hi Nikhil,

> so if anyone knows something than provide the solution/explanation.

with close to no information, it'd be simple guesswork when answering... you ought to consider to provide i.e.

- which operating system and which client software was used on the client side
- which operating system and which server software was used on the server side
- how things are set up, with the level of details dictated by the symptoms you receive
- the steps you took, leading to the symptoms
- the actual symptoms (you noted "black screen", which *may* be sufficient here )
- which steps did you took to diagnose the problem... any log file contents that may help, any debug output of client and/or server side?
- in your specific case, the network setup (client, server, connecting network) before and after the change

For instance, you wrote that you enabled IPv6 - was that on the client, the server, the network, all of these? Was it in the Linux kernel, or at some application level?

We're here to help, but we're neither super-humans nor fortune tellers

With regards,
Jens