I was able to reproduce this. DirectAdmin does actually send an error message, here's a sample header I was able to get by adding extra debug code to DA:
HTTP/1.1 404 Not found
Server: DirectAdmin Daemon v1.54.1 Registered to JBMC-Software.com
Connection: close
Content-Length: 19
Content-Type: text/html
filesize error<br>
But it does not show up in the browser.
It seems like a Chrome bug:
[url]https://bugs.chromium.org/p/chromium/issues/detail?id=174906[/url]
where the they Browser *should* be monitoring for a response while it's sending, but in this case it's not.
and it does not look like they're going to fix it anytime soon.
I've even change it to a header:
HTTP/1.1 413 Request Entry Too Large
for that case, but again, Chrome is not monitoring for it, so made no difference.
Anyway, it seems it's not a DA bug, but browser bug.
More info:
[url]https://stackoverflow.com/questions/18367824/how-to-cancel-http-upload-from-data-events[/url]
quote:
"Update: As of 4/15, Chrome may display your 413 HTML when you close the connection early. This only works when the browser is running on Linux and Mac OS X.
On Windows, Chrome still displays ERR_CONNECTION_RESET network error rather than the HTML you sent. (IE 11 and Firefox 37 continue to just show a network
error on all platforms.)"