After deploying one of my applications a user reported this error. This is the type of error I personally hate because the Exception Message is not clear to what object is it referring to.

Anyways, nothing that a quick search on Google couldn’t help. Turns out, there’s a limit for input objects in forms defined in ASP.NET since December 2011 Microsoft security patch to prevent malicious code through injection. To change this limit you have to edit your web.config file and add the following code inside your <configuration> tag.

        <add key="aspnet:MaxHttpCollectionKeys" value="your_value_here" />

Save your file and restart your IIS.