Login issue in SharePoint 2016 site (Windows Authentication)

Question

Dear Experts,

SharePoint Version : 2016
Windows Version : 2019

I am facing issue while try to login in SharePoint Site. When I try to open sharepoint application, authentication selection page for (windows and Forms) open fine, but when i select windows authentication then suddenly below error has occurred.

Answer 1

Hi @Sachin Soni ,

Here is a similar issue [Operation is not valid due to the current state of the object, when I select a dropdown list duplicate.

Issue happens because Microsoft Security Update MS11-100 limits number of keys in Forms collection during HTTP POST request. To alleviate this problem you need to increase that number.

This can be done in your application Web.Config in the <appSettings> section (create the section directly under <configuration> if it doesn’t exist). Add 2 lines similar to the lines below to the section:

<add key="aspnet:MaxHttpCollectionKeys" value="2000" />  
<add key="aspnet:MaxJsonDeserializerMembers" value="2000" />  

The above example set the limit to 2000 keys. This will lift the limitation and the error should go away.
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