2735676 - SAP Cloud Connector - TunnelHandshakeException: Timed out while waiting for response from server

SAP Cloud Connector (SCC) connection to SAP Cloud Platform does not work. Debugged SCC ljs_trace shows the following entries:

[...]
2018-10-30 15:55:30,306 +0100#INFO#com.sap.core.connectivity.tunnel.client.notification.NotificationClientEventHandler#notification-client-11-2# #Received "open tunnel event" message (packet type: 1) for tunnel id account:///<subaccount> and hostId <XXXXXXXXX>|
2018-10-30 15:55:30,307 +0100#DEBUG#com.sap.core.connectivity.tunnel.client.ManagedTunnelClient#Thread-58# #Allowed access for tunnel with id 'account:///<subaccount>' and attributes: 'applicationType:JAVA, applicationAccount:sci, applicationName:proxy'|
2018-10-30 15:55:30,308 +0100#DEBUG#com.sap.core.connectivity.tunnel.client.AbstractClient#Thread-58# #Connecting to address connectivitytunnel.hana.ondemand.com/155.56.210.84:443 using proxy /<IP of the proxy>:3128. Proxy user is |
2018-10-30 15:55:30,309 +0100#DEBUG#com.sap.core.connectivity.tunnel.client.AbstractTunnelClient#Thread-58# #Waiting the handshake with tunnel server to complete for tunnel ID: account:///<subaccount>|
2018-10-30 15:55:30,313 +0100#DEBUG#com.sap.core.connectivity.tunnel.client.AbstractClient#tunnel-client-12-2# #Successfully connected channel: [id: 0xdf3d9281, L:/<IP of the on-premise host>:11529 - R:/<IP of the proxy>:3128]. Starting handshake with tunnel server for tunnel ID: account:///<subaccount>|
[...]
2018-10-30 15:56:30,319 +0100#DEBUG#com.sap.core.connectivity.tunnel.client.AbstractClient#tunnel-client-12-2# #Tunnel handshake failed! Closing the tunnel channel immediately
com.sap.core.connectivity.tunnel.core.handshake.TunnelHandshakeException: Timed out while waiting for response from server for tunnel ID: account:///<subaccount>
[...]

• SAP CLoud Platform
• SAP Cloud Platform Connectivity
• SAP Cloud Connector

proxy, SAP Cloud connector, cloud connector, TunnelHandshakeException, Timed out while waiting for response from server, Tunnel handshake failed!, Closing the tunnel channel immediately, Tunnel handshake failed , KBA , BC-MID-SCC , SAP Cloud Connector On-Demand/On-Premise Connectivity , Problem