2017-10-23 21:16:13,960 ERROR [Long running task: PDF Space Export] [content.render.xhtml.DefaultRenderer] renderWithoutMetrics Error rendering content for view: RuntimeException occurred while performing an XHTML storage transformation (null)
 -- url: /spaces/flyingpdf/doflyingpdf.action | referer: http://host:8090/spaces/flyingpdf/flyingpdf.action?key=PUB | traceId: 28b6876076b4d8a1 | userName: f.marcaccio | action: doflyingpdf
com.atlassian.confluence.content.render.xhtml.XhtmlException: RuntimeException occurred while performing an XHTML storage transformation (null)
        at com.atlassian.confluence.content.render.xhtml.storage.StorageXhtmlTransformer.transform(StorageXhtmlTransformer.java:53)
        at com.atlassian.confluence.content.render.xhtml.TransformerChain.transform(TransformerChain.java:33)
        at com.atlassian.confluence.content.render.xhtml.TransformerChain.transform(TransformerChain.java:33)
        at com.atlassian.confluence.content.render.xhtml.PluggableTransformerChain.transform(PluggableTransformerChain.java:39)
        at com.atlassian.confluence.content.render.xhtml.DefaultRenderer.renderWithoutMetrics(DefaultRenderer.java:194)
        at com.atlassian.confluence.content.render.xhtml.DefaultRenderer.renderWithResult(DefaultRenderer.java:153)
        at com.atlassian.confluence.content.render.xhtml.DefaultRenderer.render(DefaultRenderer.java:134)
        at com.atlassian.confluence.content.render.xhtml.DefaultRenderer.render(DefaultRenderer.java:116)
        at com.atlassian.confluence.content.render.xhtml.DeviceTypeAwareRenderer.render(DeviceTypeAwareRenderer.java:49)
        at com.atlassian.confluence.extra.flyingpdf.html.RenderedXhtmlBuilder.renderToHtml(RenderedXhtmlBuilder.java:462)
        at com.atlassian.confluence.extra.flyingpdf.html.RenderedXhtmlBuilder.renderToHtml(RenderedXhtmlBuilder.java:431)
        at com.atlassian.confluence.extra.flyingpdf.html.RenderedXhtmlBuilder.renderContentTreeNodes(RenderedXhtmlBuilder.java:408)
        at com.atlassian.confluence.extra.flyingpdf.html.RenderedXhtmlBuilder.renderContentTreeNodes(RenderedXhtmlBuilder.java:416)
        at com.atlassian.confluence.extra.flyingpdf.html.RenderedXhtmlBuilder.buildHtml(RenderedXhtmlBuilder.java:125)
        at com.atlassian.confluence.extra.flyingpdf.FlyingSaucerPdfExporterService.createPdfForSpace(FlyingSaucerPdfExporterService.java:57)
        at com.atlassian.confluence.extra.flyingpdf.PdfExportLongRunningTask$1.doInTransactionWithoutResult(PdfExportLongRunningTask.java:92)
        at org.springframework.transaction.support.TransactionCallbackWithoutResult.doInTransaction(TransactionCallbackWithoutResult.java:34)
        at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:133)
        at com.atlassian.confluence.extra.flyingpdf.PdfExportLongRunningTask.doRunInternal(PdfExportLongRunningTask.java:74)
        at com.atlassian.confluence.extra.flyingpdf.PdfExportLongRunningTask.runInternal(PdfExportLongRunningTask.java:59)
        at com.atlassian.confluence.util.longrunning.ConfluenceAbstractLongRunningTask.run(ConfluenceAbstractLongRunningTask.java:26)
        at com.atlassian.confluence.util.longrunning.ManagedTask.run(ManagedTask.java:52)
        at com.atlassian.confluence.impl.util.concurrent.ConfluenceExecutors$ThreadLocalContextTaskWrapper.lambda$wrap$1(ConfluenceExecutors.java:90)
        at com.atlassian.confluence.vcache.VCacheRequestContextOperations.lambda$doInRequestContext$0(VCacheRequestContextOperations.java:50)
        at com.atlassian.confluence.impl.vcache.VCacheRequestContextManager.doInRequestContextInternal(VCacheRequestContextManager.java:87)
        at com.atlassian.confluence.impl.vcache.VCacheRequestContextManager.doInRequestContext(VCacheRequestContextManager.java:71)
        at com.atlassian.confluence.vcache.VCacheRequestContextOperations.doInRequestContext(VCacheRequestContextOperations.java:49)
        at com.atlassian.confluence.vcache.VCacheRequestContextOperations.lambda$withRequestContext$2(VCacheRequestContextOperations.java:66)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException