Hello everyone,

I am working with a Siemens S7‑1200 CPU (Firmware V4.4) in TIA Portal V16 using the LHTTP Library V1.2.
My goal is to send a POST request over HTTPS to a Postman mock server endpoint.

My System Setup

• CPU: S7‑1200, Firmware V4.4
• TIA Portal: V16
• Library: LHTTP V1.2
• Block Used: LHTTP_PostPut
• Certificate Imports:
  • *.mock.pstmn.io certificate
  • epsc.co.za certificate
  • CA certificates including ISRG Root X1

 URL 

https://ed8e0959-b5b3-45fc-a230-faeafa92673e.mock.pstmn.io/

• hwID set to 64 (HW_ANY)
• method = 0 (POST)
• contentType = Content-Type: application/json

• JSON Payload Example:

  {"sean": 2} 

Error 

• status: 16#8601
• subfunctionStatus: 16#0000_809B
• stateNumber: 3

This indicates the TLS handshake starts but fails during certificate validation, specifically a Common Name (CN) mismatch.

what am I doing wrong please, could you assist