Netlify Deploying React JS app but I can' get any page after signin

This is my first question

I created an app in React JS and Ruby on Rails. I deployed my ruby api to heroku and it’s working well. Also I deployed my react app to Netlify and I can get login page. But after loginpage i can get main page for 1 second and then it’s gone. This is my first exprience with netlify and about deploying. my code is like this for login:

render() {

return (
? <>

<Dashboard token={ this.state.token } loggedInUserId={ this.state.loggedInUserId } />
: <SignIn logInUser={ this.logInUser } />

it means if user already loggedin get Navi and Dashboard component else get singin page. That’s why if someone try to enter my app singin page coming at first.

also i upload a video to youtube about my problem you can check it out here:

and my app page:

How to fix that problem?

Hi, @CihatAldanmaz, and welcome to our Netlify community site.

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