When I tried to do processing using gpt. I was facing a new problem. The details of error are as follows :
Warning : Not able to check for new SNAP version. Remote version could not be retrieved.
Yes, I have also noticed that the server is again a bit slow at the moment and not responding well. I hope it will recover soon.
But this is only a warning and your processing should not be affected.
If you want to update SNAP from the command line you can follow this guide
From yesterday, when ever I am including a tool(apply orbit file or terrain flattening or terrain correction) which uses internet in graph file and running it using a gpt it is processing very slow and sometimes it is taking hours. 
Is this also issue with the server or is it my internal issue.
Yes, unfortunately. It is the same issue