Error Performing CJK OCR: The Request Was aborted: Could Not Create SSL/TLS Secure Channel

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02340573_Error for CJK OCR in studio

Issue:

CJK OCR is always failing with the following error message: 'Error performing OCR: An error occurred while sending the request.'

kb-0EM5b00000F3jtJ.png774×262 137 KB

The detailed error message: The request was aborted: Could not create SSL/TLS secure channel.

kb-0EMPa00000RFeTq.png694×370 332 KB

Troubleshooting:

  1. Capture Wireshark log and the TCP Client Hello handshake between Studio machine with the endpoint server (du-sg.uipath.com) always fails.
    kb-0EM5b00000F3jtO.png1780×751 78.4 KB

  2. The below required TLS Ciphers by endpoints server are missing on Robot machine (Azure VM)

    1. TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384

    2. TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256

  3. Try to enable the Cipher via Powershell commands, but failed

    1. Enable-TlsCipherSuite -Name TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384

    2. Enable-TlsCipherSuite -Name TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256

  4. Remove predefined TLS policy on Azure to allow these two ciphers

  5. Rerun the commands to enable Ciphers and restart Studio server, and check sure it's showing via Get-TlsCipherSuite commands :
    kb-0EM5b00000F3ju2.png706×526 31.2 KB

  6. Sometimes, may need to run Disable-TlsCipherSuite and Enable-TlsCipherSuite, then restart the Robots server.

Resolution:

Enable the Cipher on Studio server by remove predefined TLS policy and execute below Powershell commands:

  • Enable-TlsCipherSuite -Name TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384

  • Enable-TlsCipherSuite -Name TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256