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org.apache.sling.servlets.post.impl.operations.ModifyOperation Exception during response processing


Level 1

Hi All,


We have multiple forms which have the same POST action in the Servlet (RegistrationServlet), forms submission from all the forms go to the same POST action of the Servlet(RegistrationServlet).

We have deployed many sites which are having these forms on Prod, all the sites are hosted on the Same AEM server having two Publishers.

On Prod we are getting the following error occasionally, not regularly. 

Sometimes some forms will be throwing the following error while some other forms submission will be successful at the same time.


04.04.2017 08:52:33.584 *ERROR* [ [1491292353581] POST /content/informa/food-westafrica/en/forms/register-to-visit-for-free.html HTTP/1.1] org.apache.sling.servlets.post.impl.operations.ModifyOperation Exception during response processing.

javax.jcr.RepositoryException: org.apache.sling.api.resource.PersistenceException: Resource at '/content/informa/food-westafrica/en/forms/register-to-visit-for-free' is not modifiable.

                at org.apache.sling.servlets.post.impl.operations.ModifyOperation.doRun(ModifyOperation.java:113)

                at org.apache.sling.servlets.post.AbstractPostOperation.run(AbstractPostOperation.java:92)

                at org.apache.sling.servlets.post.impl.SlingPostServlet.doPost(SlingPostServlet.java:202)


We have registred the Servlet using path.

I did some analysis on google, found that the Servlet should be Registered as ResourceType, so that this error will not occur. But my question here is, if this is the cause for the problem why this issue does not occur for all the forms submission which are posting the data to the same Servlet at the same time, why some forms fail and others not.

We have cloud fronts configured in front of dispatchers, and we do deployment to Prod every two weeks and in our current process we don't clear the Cloud front cache and dispatcher cache.


I have attached error log and screen-shot of the error we are getting, please let us know what could be the cause of the issue if you have encountered this issue before in your project.

6 Replies


Level 3


Am also facing same issue .
you found a solution please share to help us to overcome.

hi smacdonald2008​ please suggest us some solution

AM referring below url to overcome :


Check if its recovered your issue!


Level 10

Were you able to validate the configurations mentioned in that article?

Could you check if the servlet is registered properly in the Felix-bundles/components tab and share complete request/response including headers from "network" tab of developer toolbar?

Did this servlet ever work before in the past or this is the first time you have deployed this servlet?


Adobe Champion

@Karthi45 Did you get a solution to this problem? I am also facing the same issue


Adobe Champion

@pavankumarb2683 Did you get a solution to this problem? I am also facing the same issue


Level 1

Hi Did you get any solution, I am facing same issue and intermittently getting 500 from servlet.


Level 1

I faced this issue ( & 409 conflict error )

Its more generic error. Servlet is not able to correctly instantiated. It may be due to many reason due to which dependency is not able to resolved.

1.In my case the service which was getting Reference in servlet was not properly annotated.

2. Servlet path is not unique