3652241 - HTTP 503 Service Unavailable error while opening subaccount tunnel from SAP Cloud Connector towards BTP

• The subaccount tunnel from the SCC stops working suddenly.
• Following entries are there in the in SCC trace (ljs_trace.log (<2.17)/scc_core.trc (>=2.17)):
  
  #ERROR#com.sap.core.connectivity.tunnel.core.handlers.TunnelClientErrorHandler#notification-client-38-1#          
  #Unexpected problem during tunnel processing in channel [id: xxxxxxxxxx, L:0.0.0.0/0.0.0.0:xxxxx ! R:<proxy Server>:<proxy Port>]; Reason: Invalid status of handshake response: 503 Service Unavailable; Exception type: com.sap.core.connectivity.tunnel.core.handshake.TunnelHandshakeException
  
  #ERROR#com.sap.core.connectivity.tunnel.client.handshake.ClientProtocolHandshaker#notification-client-38-1#          #Invalid status of handshake response: DefaultHttpResponse(decodeResult: success, version: HTTP/1.1)
  HTTP/1.1 503 Service Unavailable
  date: xxx, xx xxx 202X xx:xx:xx
  connection: close
  content-length: 0

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

• SAP Cloud Connector release independent.
• SAP Business Technology Platform (BTP).

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