Connection with Secure Tunnel is not established.

I am trying to build a C++ client application using AWS IoT Device SDK V2. I am using IoT service apis. I application is not able to establish a stable connection. I am getting success from connect API but immediately it terminating. I am not getting the possible root cause and solution. I need some solution or clue. Thanks in advance.

Application log:

Connection attempt failed with error code 2065(aws-c-io: AWS_IO_READ_WOULD_BLOCK, Read operation would block, try again later)

AWS SDK Log:

[tls-handler] - id=0x7f8644003060: Bytes read 376 [channel] - id=0x7f8644002d60: sending read message of size 376, from slot 0x7f863c004640 to slot 0x7f864402b770 with handler 0x7f8644029458. [http-connection] - id=0x7f8644029450: Incoming message of size 376. [http-stream] - id=0x7f86440170a0: Incoming response status: 426 (Upgrade Required). [http-stream] - id=0x7f86440170a0: Incoming header: content-type: application/json [http-stream] - id=0x7f86440170a0: Incoming header: content-length: 98 [http-stream] - id=0x7f86440170a0: Incoming header: date: Tue, 11 Jul 2023 09:49:42 GMT [http-stream] - id=0x7f86440170a0: Incoming header: x-amzn-RequestId: 0db4750f-4c3b-867b-a49d-798f5096793c [http-stream] - id=0x7f86440170a0: Incoming header: connection: keep-alive [http-stream] - id=0x7f86440170a0: Incoming header: x-amzn-ErrorType: InternalFailureException: [http-stream] - id=0x7f86440170a0: Incoming header: sec-websocket-version: 13,8,7 [http-stream] - id=0x7f86440170a0: Main header block done. [http-stream] - id=0x7f86440170a0: Incoming body: 98 bytes received. [http-stream] - id=0x7f86440170a0: Client request complete, response status: 426 (Upgrade Required). http-connection] - id=0x7f8644029450: Shutting down connection with error code 0 (AWS_ERROR_SUCCESS). [channel] - id=0x7f8644002d60: channel shutdown task is scheduled [channel] - id=0x7f8644002d60: scheduling task with wrapper task id 0x7f8644002f60. [event-loop] - id=0x7f864c000ae0: scheduling task 0x7f8644002f60 in-thread for timestamp 0 [task-scheduler] - id=0x7f8644002f60: Scheduling channel_shutdown task for immediate execution [http-stream] - id=0x7f86440170a0: Stream refcount released, 1 remaining. [http-stream] - id=0x7f86440170a0: Final stream refcount released. [http-connection] - id=0x7f8644029450: Connection refcount released, 1 remaining. [http-connection] - id=0x7f8644029450: Current incoming stream is now (nil). [http-connection] - id=0x7f8644029450: Decoded 376 bytes of message, 0 bytes remain.