Error when using api call to send post values to controller and mapping them with a dto

I have two webpages, the first has a dropdown that allows the person to select a project & a button. When the button is submitted, it takes them to the manage users webpage and sends the Projectname to the webpage as well. The manage users webpage allows the person to assign a user to the project they selected on the previous webpage. There is a button as well, and when submitted it sends an api call with post values to my controller. The controller accepts a dto and then binds these values to the AssignUserDto. It then finds the entity associated w/ the dto username, and then maps the values from the dto to the entity so that the user has a Projectname associated with it.

Asp.NET Core + ReactJs – What is the correct way to store authentication information?

After analyzing a lot of examples online and the asp.net core + react authentication given template, I noticed that all of them do NOT use redux store. At first I tough that you should not use them but it could also be just an example application to show roughly how to execute it in a simple manner.