added check for undefined

lib/plugins/pagexray/index.js

@@ -82,6 +82,8 @@ export default class PageXrayPlugin extends SitespeedioPlugin {
             firstParty: this.options.firstParty ?? undefined
           };
           const pageSummary = pagexray.convert(message.data, config);
+          if (!pageSummary) break;
+
           //check and print any http server error > 399
           for (let summary of pageSummary) {
             if (Object.keys(summary.responseCodes).some(code => code > 399)) {