/libs/wcm/core/content/misc node get resolved to /miscadmin in aem and one of author has updated this node. That was the root cause of the issue. i reverted it back and it starts working.

Thanks all for your opinion. i was able to fix it

what did you checked in /etc/workflow

admin user also have same issue...

Nothing new came up. same issue

Yes, its enabled

yes, it happens after we upgraded to 6.3.2.1. But it didn't started immediately after service pack installation

the error.log shows below logGET /miscadmin HTTP/1.1] libs.cq.workflow.components.collection.definition.resource.resource$jsp error while rendering resource: java.lang.NullPointerException: null at org.apache.jsp.libs.cq.workflow.components.collection.definition.resource.resource_jsp._jspService(resource_jsp.java:165)

Network tab shows response 200 ok. I tried updating the Json.maximumresults = 100000 but with no luck.