Have you seen this Firefox error:

"Connection Interrupted | The connection to the server was reset while the page was loading."

Internet Explorer has its own version.

It is displayed when you are uploading a file through browser interface or when you are submitting large forms.

There may be several reasons, but I'll share my situation in case you encounter the same thing. I had experimented with my Netgear router's content filtering settings by adding keyword blocking. Later on I did clear the keywords but inadvertantly kept Keyword Blocking option checked "Always" although there were no keywords. This was the cause of the error message.

It took me a while to figure this out. There was no solution offered online anywhere else so I traced back the changes I made to the router.

So, just in case you are seeing the same error message, check your router's settings.