why am i getting this "Checking the proxy and the firewall" and what to do?

[Kavya Saritha]

i am started jira practise but it was not working .one day its working fine and the next day its not working. 

[Tuncay Senturk _Snapbytes_]

Hi @Kavya Saritha 

Welcome to the Atlassian Community!

Could you please provide more information? Is your Jira up and running? Have you tried different browsers? Sometimes cleaning the browser cache also helps. 

It might also be a network/proxy server issue. The devil is in details, we need more information.