To receive RTSP feed at server we need to install NginX and RTMP module at server side. 

Then we need to configure rtmp configure at nginx.conf from /etc/nginx/nginx.conf

rtmp {

    server {

        listen 8000; # Listen on standard RTMP port

        chunk_size 4000;


        application live {

            live on;

            # Turn on HLS


            # HLS Configuration

      hls on;

      hls_path /var/www/chatapp.thinkfoundation.com.bd/hls/;

      hls_fragment 3;

      hls_playlist_length 60;


      # Use a custom name for the HLS segment files


            hls_fragment_naming system;

            hls_fragment_naming_granularity 1;

        }

    }

}


and also update the server block of nginx config file. It could be nginx.conf or /etc/nginx/sites-available/ folder config file.

Use following server block to get the hls feed

server {
    listen 80;
    server_name chatapp.thinkfoundation.com.bd;  # replace with your domain or IP address

    location / {
        root /var/www/chatapp.thinkfoundation.com.bd/hls/;  # replace with the path to your HLS files
        add_header Cache-Control no-cache;
        add_header 'Access-Control-Allow-Origin' '*' always;
        # You can add more headers as needed

        # Enable CORS for HLS
        if ($request_method = 'OPTIONS') {
            add_header 'Access-Control-Allow-Origin' '*';
            add_header 'Access-Control-Max-Age' 1728000;
            add_header 'Content-Type' 'text/plain charset=UTF-8';
            add_header 'Content-Length' 0;
            return 204;
        }

        # Handle HLS files
        location ~ \.m3u8$ {
            types { application/vnd.apple.mpegurl m3u8; }
            add_header Cache-Control no-cache;
            add_header 'Access-Control-Allow-Origin' '*' always;
            # You can add more headers as needed
        }

        location ~ \.ts$ {
            add_header Cache-Control no-cache;
            add_header 'Access-Control-Allow-Origin' '*' always;
            # You can add more headers as needed
        }
    }
}


Now your live feed url will be: 
example 
http://chatapp.thinkfoundation.com.bd/.m3u8


Make sure that you send your local rtsp feed to remote server using following command:

ffmpeg -i "rtsp://admin:hik12345@192.168.100.40:554/Streaming/Channels/101" -filter:v fps=fps=30 -crf 40 -preset ultrafast -vcodec libx264 -f flv "rtmp://157.245.58.124:8000/live"

you need ffmpeg library to execute upper command to send rtsp feed to rtmp server.