HELP !!! Weblink - ASP.NET Core- Main channel closes the connection with error code 1003 after successful handshake upon


I have started developing cloud printing solutions based on Zebra printers. I have been referring Weblink Endpoint Configuration document available here -

I was able to successfully connect with printer. Post successful handshake, i am sending the JSON message to open the Raw channel. But immediately after that, printer is sending the close connection request. I have confirmed by downloading logs from the printer. I have noticed that it is unable to read the JSON message which i have sent on the Main Channel. The below are the specific logs about the error.

[12-26-2019 08:26:32.772][Info][800B03EB][conn2.1] Closing connection with code 1003
[12-26-2019 08:26:32.787][Error][0000101D][conn2.1] Read failed with an unexpected error

When I tried to understand the error code 1003, it is used when the client is unable to understand the message because it is unexpected format.

Based on the document, I am sending JSON message to the Main Channel.

Can someone please help me?

Thanks and Regards,