Merge pull request #18183 from ghalliday/issue31063

HPCC-31063 Improve the error message when failing to connect to a host ip

Reviewed-by: Mark Kelly mark.kelly@lexisnexisrisk.com
Merged-by: Gavin Halliday <ghalliday@hpccsystems.com>

common/thorhelper/thorsoapcall.cpp

@@ -2407,6 +2407,9 @@ class CWSCAsyncFor : implements IWSCAsyncFor, public CInterface, public CAsyncFo
                     checkTimeLimitExceeded(&remainingMS);
                     Url &connUrl = master->proxyUrlArray.empty() ? url : master->proxyUrlArray.item(0);
                     ep.set(connUrl.host.get(), connUrl.port);
+                    if (ep.isNull())
+                        throw MakeStringException(-1, "Failed to resolve host '%s'", nullText(connUrl.host.get()));
+
                     checkTimeLimitExceeded(&remainingMS);  // after ep.set which might make a potentially long getaddrinfo lookup ...
                     if (strieq(url.method, "https"))
                         proto = PersistentProtocol::ProtoTLS;