Any idea on 12031 server con reset? How to resolve?

Question

I'm getting this err on a page with a grid, viewstate enabled. only when theres a huge number of rows in the grid this happens.

Answer 1

That's not an HTTP error code (those have 3 digits). General trend on Google is an ASP Inetd error:

12031 ERROR_INTERNET_CONNECTION_RESET : The connection with the server has been reset.

Servers RST connections when something goes wrong / you're sticking around too long / they want your client to stop talking.
I'd start with 'why' it's happening. Find the ASP logs or turn them on*, because the causes could be many.

For example:
Takes too long?
Send less data. Compress it. Send it in chunks (websockets, XMLHTTPRequest, fetch(), AJAX, etc).
Don't send the entire HTML - just send a JSON object and make the client build it.
Optimize the server, the client or the connection.
Make sure the connection closes, the query completes, and the last frame is actually sent (not just sitting in a buffer because the buffer isn't full).

Other things can cause transient resets (more likely to happen in long queries) like:
bad protocol (probably TCP), outdated drivers, faulty wires, incompatible modules, software problems, network congestion, etc.

* On a computer, you can also use Chrome/Firefox's Developer Console (or add Firebug) to look closer at the browser's behavior.