The proxy server refuses to accept connections, what should I do?

Question

Browsers

Folks, this is the problem. Yesterday everything was fine. Today does not go to any site. Ping does not go to them. On other computers on the network everything is OK. Kerio is installed on a separate machine, a proxy is registered. It also stands in the "browser properties". Without this registration in the properties usually did not work. In addition, the gateway does not ping from the problem machine - 100% loss. What else I noticed in Bitorrent is the distribution, but naturally it does not download.
the network shared drives from the file server enters.N The
proxy server refuses to accept connections
Firefox is configured to use a proxy server that refuses the connection.
* Check your proxy settings and make sure they are correct.
* Contact your system administrator and make sure the proxy server is working.
0. Banal Restart of the machine and Kerio.
1. Checked on other browsers (Opera, Chrome, IE) nothing changes.
2. Disabled AdBlock in these browsers, also by.
3. Cleared cookies on all browsers.
4. Turned off the firewall.
nslookup

Proxy tab in Kerio

Logs

Answer 1

So, first of all. Gateway and proxy server are very weakly connected. If the proxy server is located on the same network as the target computer, then the gateway on the network card of the target PC may not be specified at all, proxying is used to process traffic, and traffic will go directly to the proxy itself. If the proxy is in another network, then in order to reach it, the traffic will go through the router of this network (proxy network, this will not necessarily be the main gateway - the default gateway).
Now in your case. Ping does not go - we check the settings of the gateway, network, firewall.
The proxy does not allow traffic - check the firewall settings, network settings.
In general, the situation is strange and the diagnostic methods are not the same. In the logs, there is generally one solid UPnP (read as "connections that do not require configuration"). It is very likely that DHCP went pi*de or the addressing went astray.
Required:
1. telnet to the proxy address, to the proxy port, there should be a response.
2. Ping to proxy address, should be answered
3. Ping to DNS, should be answered
4. nslookup to DNS Sverera, should be answered.
Maybe they just poked something in the firewall, or the rules were changed in some places.

Answer 2

check all settings (compare with working ones from another machine). especially pay attention to the fact that you seem to have a wrong gateway / proxy or both =)))