Inconsistent Access Denied Page

Hi All,

 

Below screenshot is my landing page which is in start process form, where this is the page where you can see a dropdown and a box layout, and the bottom fields is empty, Ideally there is no sail code written.But still we are able to see the Access Denied dialog Box which is making users to get confused,

 

May i know what could be causing the issue, and if so what are the actions i need to take, I have seen security to each and every object and rule, 

 

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