Error while getting response from load balancer

I have deployed react application on Application load balancer and there are two ec2 instance in a target group,the issue is that the web page loads properly after multiple refresh or else gives blank screen because of the error "Uncaught SyntaxError: Unexpected token '<'". in the console and only loads the static index.html.

The application loads by directly accessing the instance without any error and even after multiple refreses. The issues get encountered in load balancer only. I have also tried changing the health check configuration but didn't worked and the checkups are also healthy. I also tried deploying the application with classic load balancer but issues were faced.

What might be the possible issue because it successfully responds sometimes and mostly reponds with errors?