Example of errors vary, most as per prior comment are only firefox messages that suggest site might be down, try again later etc..
But also today
Proxy Error
The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /qatracker/milestones/429/builds/246318/testcases/1701/results.
Example of errors vary, most as per prior comment are only firefox messages that suggest site might be down, try again later etc..
But also today
Proxy Error
The proxy server received an invalid response from an upstream server. milestones/ 429/builds/ 246318/ testcases/ 1701/results.
The proxy server could not handle the request GET /qatracker/
Reason: Error reading from remote server