Ajax indicator keeps on spinning when "sitemap.xml" is clicked under "Pages".

Please check the attached browser console errors when "sitemap.xml" is clicked.
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Resource interpreted as Document but transferred with MIME type application/xml: "http://cms.demo.test.onehippo.com/site/sitemap.xml".IFramePanel-ver-1429193832000.js:88 Hippo.IFramePanel.Ext.extend.setLocationpage-editor-all-ver-1429196186000.js:1518 (anonymous function)ext-base-ver-1425155566000.js:2 (anonymous function)page-editor-all-ver-1429196186000.js:1536 (anonymous function)ext-base-ver-1425155566000.js:2 (anonymous function)ext-all-ver-1425155566000.js:2 Ext.extend.handleResponseext-wicket-adapter-ver-1425155566000.js:18 Ext.lib.Ajax.request.cb.successext-base-ajax-ver-1425155566000.js:106 handleTransactionResponseext-base-ajax-ver-1425155566000.js:151 checkResponseext-base-ver-1425155566000.js:2 (anonymous function)

IFramePanel-ver-1429193832000.js:162 Uncaught TypeError: Cannot read property 'appendChild' of undefinedIFramePanel-ver-1429193832000.js:162 api.flushpage-editor-all-ver-1429196186000.js:1362 (anonymous function)ext-base-ver-1425155566000.js:2 (anonymous function)future-ver-1429193832000.js:30 Future.whenjquery-1.11.2.min-ver-1425155568000.js:2 m.extend.proxy.m.isFunction.epage-editor-all-ver-1429196186000.js:1341 (anonymous function)ext-base-ver-1425155566000.js:2 (anonymous function)future-ver-1429193832000.js:15 Futurefuture-ver-1429193832000.js:120 Hippo.Futurepage-editor-all-ver-1429196186000.js:1340 Hippo.ChannelManager.TemplateComposer.PageContext.Ext.extend._initializeIFrameHeadpage-editor-all-ver-1429196186000.js:1184 (anonymous function)ext-base-ver-1425155566000.js:2 (anonymous function)future-ver-1429193832000.js:96 Future.onSuccessfuture-ver-1429193832000.js:16 (anonymous function)page-editor-all-ver-1429196186000.js:1298 (anonymous function)future-ver-1429193832000.js:96 Future.onSuccessfuture-ver-1429193832000.js:16 (anonymous function)future-ver-1429193832000.js:160 Hippo.Future.join.Hippo.Future.successHandlerfuture-ver-1429193832000.js:96 Future.onSuccessfuture-ver-1429193832000.js:16 (anonymous function)page-editor-all-ver-1429196186000.js:1255 Hippo.ChannelManager.TemplateComposer.PageContext.Ext.extend._initPageModelStore.Hippo.Future.stores.pageModel.on.singleext-all-ver-1425155566000.js:2 (anonymous function)ext-all-ver-1425155566000.js:2 h.Event.fireext-all-ver-1425155566000.js:2 h.Observable.fireEventext-all-ver-1425155566000.js:2 Ext.data.Store.Ext.extend.loadRecordsext-all-ver-1425155566000.js:2 Ext.extend.onReadext-all-ver-1425155566000.js:2 (anonymous function)ext-all-ver-1425155566000.js:2 Ext.extend.handleResponseext-wicket-adapter-ver-1425155566000.js:18 Ext.lib.Ajax.request.cb.successext-base-ajax-ver-1425155566000.js:106 handleTransactionResponseext-base-ajax-ver-1425155566000.js:151 checkResponseext-base-ver-1425155566000.js:2 (anonymous function)