Proxy connection hangs

If I try to get data over proxy, reply will timeout - isRunning will return true infinitely, result from readLine() is empty
I can see in proxy server log that request was successful.

QUrl lourl("http://qt-project.org/");
QNetworkAccessManager lonam;
QNetworkProxyQuery lonpq(lourl);
QList<QNetworkProxy> lolist_proxy = QNetworkProxyFactory::systemProxyForQuery(lonpq);
bool lbchecked = false;
QString lserrors;
bool lblatest = false;
for (QList<QNetworkProxy>::const_iterator Loit = lolist_proxy.constBegin(); Loit != lolist_proxy.constEnd(); Loit++) {
QNetworkRequest lonr(lourl);
if (Loit->port() > 0)

{ vlog("trying: "+Loit->hostName()+':'+QString::number(Loit->port()), true); }

lonam.setProxy(*Loit);
auto Lonreply = lonam.get(lonr);
if (Lonreply) {
int loops = 30;
while ((loops > 0) && Lonreply->isRunning()) {
if (!abloop)

{ Lonreply->abort(); return; }

loops--;
sleep(1);
vlog(Lonreply->readLine(), true);
}
if (!loops)

{ lserrors.append("timeout, ").append(QString::number(Lonreply->error())); continue; }