Having said that workaround available is:
1) Use JasperSoft 6.1 (If you encounter any report issue which is developed in JasperSoft 6.2.x and updated in JasperSoft 6.1) then please recompile the report using JasperSoft 6.2.1
2) Work with JasperSoft Studio 6.2.x or later release from outside corporate network with Active Provider set to 'Direct' and no manual Proxy configuration.
3) Or have network security team bypass the JasperSoft Server IP addresses for specific client machine to connect studio from.
4) And in case if you have an active CA VPN access get connected through it which will give you a successful connection without configuring Studio PROXY.