[Solved] ASP.Net Core Error: Internal Server Error 500

In development the login and register work but in production it is not, why is that?

in account controller (API) I have the below code to login the user. I am using this example because it is shorter to demonstrate.

[HttpPost("login")]
public async Task<IActionResult> Login(loginReqDto loginReq)
{
    var user = await uow.UserRepository.Authenticate(loginReq.UserName, loginReq.Password);
 
    ApiError apiError = new ApiError();
 
    if(user == null)
    {
        apiError.ErrorCode = Unauthorized().StatusCode;
        apiError.ErrorMessage = "Invalid userId or Password!";
        apiError.ErrorDetails = "This is appearing when user or password does not exist!";
        return Unauthorized(apiError);
    }
 
    var loginRes = new LoginResDto();
    loginRes.UserName = user.Username;
    loginRes.Token = CreateJWT(user);
    return Ok(loginRes);
}

and in my front end (angular):

onlogin(loginForm: NgForm){
 
console.log(loginForm.value);
this.authServive.authUser(loginForm.value).subscribe(     
  (response: any) => {
    console.log(response);
    const user = response;
    localStorage.setItem('token', user.token);
    localStorage.setItem('userName', user.userName);
    this.alertify.success("You have loged-in successfully!");
    this.router.navigate(['/']);
  });
}

In postman using development I am getting the code 200OK and generated the token. on the otherhand, in production, I get internet server error code 500.

why?