Connection Lost Saving Posts

Hi!

I’m having problems saving posts. I get the “Lost Connection” message once I begin editing or writing a post and the “publish” and “save draft” buttons greyed out.

This is a multisite installation over IIS with a domain mapping plugin. Problem happens in every blog of the network.

Tried a whole bunch of solutions no to result.
These are my web.config and wp-config.php archives.

Web Config:

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.webServer>
		<httpProtocol>
			<customHeaders>
				<add name="Access-Control-Allow-Origin" value="*" />
			</customHeaders>
		</httpProtocol>
		<defaultDocument>
            <files>
                <clear />
                <add value="index.php" />
                <add value="Default.htm" />
                <add value="Default.asp" />
                <add value="index.htm" />
                <add value="index.html" />
                <add value="iisstart.htm" />
            </files>
        </defaultDocument>
		<rewrite>
			<rules>
				<rule name="WordPress Rule 1" stopProcessing="true">
					<match url="^index\.php$" ignoreCase="false" />
					<action type="None" />
				</rule>
				<rule name="WordPress Rule 2" stopProcessing="true">
					<match url="^([_0-9a-zA-Z-]+/)?wp-admin$" ignoreCase="false" />
					<action type="Redirect" url="{R:1}wp-admin/" redirectType="Permanent" />
				</rule>
				<rule name="WordPress Rule 3" stopProcessing="true">
					<match url="^" ignoreCase="false" />
					<conditions logicalGrouping="MatchAny">
					<add input="{REQUEST_FILENAME}" matchType="IsFile" ignoreCase="false" />
					<add input="{REQUEST_FILENAME}" matchType="IsDirectory" ignoreCase="false" />
					</conditions>
					<action type="None" />
				</rule>
				<rule name="WordPress Rule 4" stopProcessing="true">
					<match url="^" ignoreCase="false" />
					<conditions logicalGrouping="MatchAny">
					<add input="{REQUEST_FILENAME}" matchType="IsFile" ignoreCase="false" />
					<add input="{REQUEST_FILENAME}" matchType="IsDirectory" ignoreCase="false" />
					<add input="{URL}" pattern="([a-zA-Z0-9\./_-]+)\.axd" />
					</conditions>
					<action type="None" />
				</rule>
				<rule name="WordPress Rule 5" stopProcessing="true">
					<match url="^[_0-9a-zA-Z-]+/(wp-(content|admin|includes).*)" ignoreCase="false" />
					<action type="Rewrite" url="{R:1}" />
				</rule>
				<rule name="WordPress Rule 6" stopProcessing="true">
					<match url="." ignoreCase="false" />
					<action type="Rewrite" url="index.php" />
				</rule>
			</rules>
		</rewrite>
		<httpRedirect enabled="false" destination="https://www.kpmgblogs.es" />
    </system.webServer>
</configuration>

And this is the multisite part in wp-config.php:

define('MULTISITE', true);
define('SUBDOMAIN_INSTALL', true);
define('DOMAIN_CURRENT_SITE', 'kpmgblogs.es');
define('PATH_CURRENT_SITE', '/');
define('SITE_ID_CURRENT_SITE', 1);
define('BLOG_ID_CURRENT_SITE', 1);
define('SUNRISE', true);

define('CONCATENATE_SCRIPTS', false);

There is another pair of problems. I just can’t get the add new plugin page. I get an error that says “An unexpected error occurred. Something may be wrong with www.remarpro.com or this server’s configuration. If you continue to have problems, please try the support forums”.

And I get “RSS Error: WP HTTP Error: Failed connect to es.www.remarpro.com:80; No error” & “RSS Error: WP HTTP Error: Failed connect to planet.www.remarpro.com:443; No error” in the dashboard.

Any ideas??