Invalid postback or callback argument. Event validation is enabled using

I tried to do it with list lookup, but the problem was that the values added by jquery was lost when I submitted the form, any ideas??

In my case, I was manipulating list lookup controller options using javascript, and that was making my problem. I figured this after one week of searching for my problem  

Thanks ‌ for your reply.

Amine Charraqua‌ 

At times there could a couple a white spaces in Drop Down spaces in your unbound fields within the form.
Remove the white spaces for all the drop down lists within Nintex form and it should work. 

Hi All, 

I found the same issue.. I am dynamically preparing the dropdown values and while appending the final text to the dropdown there was a space. After removing the space i did not observe any error.

Was this ever solved?

I'm having the exact same issue, but I'm not sure what it's meant by 'remove the white space'.

Where do I remove the space?

I was able to work through my issue, although it's not ideal. I plan to post my solution in detail, but I did give a basic explanation of how I accomplished it on this post.

Has anyone found a solution to this issue? I am using a dropdown choice field. I am appending values to the existing choices through jquery. But when I am selecting anything from additional choices added through jquery, my form throws an error. It works fine with values added through the list.

This is the error I am getting:

Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.

Have you found a solution yet?