Angular SignalR is not working with AWS Load Balancer Proxy URL

I am using signalR between my Angular with library @aspnet/signalr and .NET Core application. It is working fine on local machine and as well on IIS.

I want to use custom URL so I have applied Proxy through AWS Load Balancer so the API URL looks like https://api.example.com. It also works fine with Load Balancer URL.

With proxy URL, it gives an error failed: Error during WebSocket handshake: Unexpected response code: 400. Any suggestions to sort out this issue?

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