Debug serverside validation

Hi 

I'm trying to use server side (re-)validation. So I've enabled Server Validation in the form's Submit Action Dialog and I've specified the name of the clientlib into the Styles-Tab (see attached screenshots). It's the same clientlib I use clientside.

When I try to submit a form containing data validation succeeds on clientside but fails on serverside. Hence I assume that something went wrong when the validation expressions were evaluated. I guess that not all dependencies where available on serverside.

In error.log I can't see no error

24.02.2017 17:06:18.553 *WARN* [0:0:0:0:0:0:0:1 [1487952378408] POST /..xy../jcr:content/guideContainer.af.internalsubmit.jsp HTTP/1.1] com.adobe.aemds.guide.utils.SubmitDataCollector templateKey not found in merge json:guideGlobalLazyField 24.02.2017 17:06:24.289 *INFO* [0:0:0:0:0:0:0:1 [1487952378707] POST /..xy../jcr:content/guideContainer.af.submit.jsp HTTP/1.1] org.apache.sling.scripting.javascript.helper.SlingGlobal [  Envjs/1.6 (Rhino; U; Windows 7 amd64 6.1; en-US; rv:1.7.0.rc2) Resig/20070309 PilotFish/1.2.13  ] 24.02.2017 17:06:25.607 *INFO* [0:0:0:0:0:0:0:1 [1487952378707] POST /..xy../jcr:content/guideContainer.af.submit.jsp HTTP/1.1] com.adobe.aemds.guide.service.impl.GuideModelTransformerImpl Server side validation errors for the Adaptive Form :- /..xy../jcr:content/guideContainer 24.02.2017 17:06:25.607 *INFO* [0:0:0:0:0:0:0:1 [1487952378707] POST /..xy../jcr:content/guideContainer.af.submit.jsp HTTP/1.1] com.adobe.aemds.guide.service.impl.GuideModelTransformerImpl SomExpression: guide[0].guide1[0].guideRootPanel[0].panelXY[0].fldXY[0] ErrorMessage:    There is a validation error in the field.

Now I'm wondering how I can debug serverside evaluation of the validation expressions. Or is there any possibility to trace the serverside evaluation of the validation expressions?

Thanks,

Urs