Errors thrown when inner frame is not available

Start with BaseFrameElement.loadInnerPageIfPossible, the frame-loading entry point named in the stack trace, and inspect how failed inner-page requests are handled. Reproduce with an iframe whose host fails DNS or TLS resolution; done means the failure is handled as requested without an unsuppressible error, with a regression test covering the case.

My site runs a DNS blocker filtering the regex "betsonsport.ru", returning NXDOMAIN for any query. When trying to load content from this domain into a frame, regular browsers stay silent and display white space or a warning sign instead.

HtmlUnit throws an error that cannot be suppressed with all the error silencers. In my view, no connection attempt should be made at all.

Error snippet:
Mai 16, 2025 12:59:32 PM org.htmlunit.html.BaseFrameElement loadInnerPageIfPossible
SCHWERWIEGEND: IOException when getting content for iframe: url=[https://www.betsonsport.ru/banners/lend4.php]
javax.net.ssl.SSLHandshakeException: (certificate_unknown) PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at java.base/sun.security.ssl.Alert.createSSLException(Alert.java:130)
at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:383)
at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:326)
at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:321)
at java.base/sun.security.ssl.CertificateMessage$T13CertificateConsumer.checkServerCerts(CertificateMessage.java:1326)
at java.base/sun.security.ssl.CertificateMessage$T13CertificateConsumer.onConsumeCertificate(CertificateMessage.java:1203)
at java.base/sun.security.ssl.CertificateMessage$T13CertificateConsumer.consume(CertificateMessage.java:1146)
at java.base/sun.security.ssl.SSLHandshake.consume(SSLHandshake.java:393)
at java.base/sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:476)
at java.base/sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:447)
at java.base/sun.security.ssl.TransportContext.dispatch(TransportContext.java:206)
at java.base/sun.security.ssl.SSLTransport.decode(SSLTransport.java:172)
at java.base/sun.security.ssl.SSLSocketImpl.decode(SSLSocketImpl.java:1507)
at java.base/sun.security.ssl.SSLSocketImpl.readHandshakeRecord(SSLSocketImpl.java:1422)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:455)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:426)
at org.apache.http.conn.ssl.SSLConnectionSocketFactory.createLayeredSocket(SSLConnectionSocketFactory.java:436)
at org.apache.http.conn.ssl.SSLConnectionSocketFactory.connectSocket(SSLConnectionSocketFactory.java:384)
at org.htmlunit.httpclient.HtmlUnitSSLConnectionSocketFactory.connectSocket(HtmlUnitSSLConnectionSocketFactory.java:176)
at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:142)
at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:376)
at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:393)
at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:236)
at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:186)
at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89)
at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:72)
at org.htmlunit.HttpWebConnection.getResponse(HttpWebConnection.java:191)
at org.htmlunit.WebClient.getWebResponseOrUseCached(WebClient.java:1726)
at org.htmlunit.WebClient.loadWebResponseFromWebConnection(WebClient.java:1631)
at org.htmlunit.WebClient.loadWebResponse(WebClient.java:1556)
at org.htmlunit.WebClient.getPage(WebClient.java:485)
at org.htmlunit.WebClient.getPage(WebClient.java:402)
at org.htmlunit.html.BaseFrameElement.loadInnerPageIfPossible(BaseFrameElement.java:211)
at org.htmlunit.html.BaseFrameElement.loadInnerPage(BaseFrameElement.java:121)
at org.htmlunit.html.HtmlPage.loadFrames(HtmlPage.java:1898)
at org.htmlunit.html.HtmlPage.initialize(HtmlPage.java:267)
at org.htmlunit.WebClient.loadWebResponseInto(WebClient.java:701)
at org.htmlunit.WebClient.loadWebResponseInto(WebClient.java:575)
at org.htmlunit.WebClient.getPage(WebClient.java:493)
at org.htmlunit.WebClient.getPage(WebClient.java:402)
at org.htmlunit.WebClient.getPage(WebClient.java:538)
at org.htmlunit.WebClient.getPage(WebClient.java:520)