I was trying to resolve issue related to "Collaborative Editing" and I requested my Linux admin to open port 8091 for this purpose.
Not sure suddenly I am not able to access the confluence application from UI.
The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /.
Reason: Error reading from remote server
Is this issue something related to application level ? or Network level ?
Please advice on how to troubleshoot this issue.