3606858 - 504 Error in BTP CAP Application which is connecting to S/4HANA

504 gateway timeout error occurs when calling a request from CAP application to S/4HANA on-premise system after 30s.

The flow is: approuter --- srv-api ---> CAP service --- destination ---> backend (S/4HANA on premise system).

In the destinations which is to backend, already add "HTML5.Timeout" in the additional property and set it as 120000 ms. But the issue persists.

An example is:
Reproduce the issue and collect HTTP trace following below: 
KBA 1990706 - How to capture an HTTP trace using Google Chrome or MS Edge (Chromium)
In the HTTP trace, there is a POST request to /<xxxxx>/odata/v4/<xx>/$batch completed with status 504.
The content of the response is: Gateway Timeout

 "Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental."

• SAP Business Technology Platform -SAP BTP
• SAP Business Application Studio - SAP BAS
• SAP Cloud Application Programming Model - SAP CAP
• Cloud Foundry - CF

504, BTP CAP, S/4HANA, HTML5.Timeout, SAP BTP Application Router, mta.yaml, timeout, xs-app.json, gateway timeout , KBA , BC-CP-APR , SAP BTP Application Router , Problem