3693342 - Access denied to resource, in case this was a valid request, ensure to expose the resource correctly in your cloud connector

While triggering an SAP BTP application, following error is returned:

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Access denied to resource http://<virtual-host>:443/sap/API_<CUSTOMER_PROCESS>_PROCESS_SRV/$metdata/ on system <virtual-host>:443. In case this was a valid request, ensure to expose the resource correctly in your cloud connector.
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And upon checking SCC trace (ljs_trace.log / scc_core.trc), following is raised:

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20xx-xx-xx xx:xx:xx,xxx +0200#DEBUG#com.sap.core.connectivity.protocol.http.handlers.HttpRequestStateHandler#tunnel-client-516-3#0x817291d4#Start sending http://<virtual-host>:443/<customer-service>-group.com/sap/opu/odata/sap/API_<CUSTOMER_PROCESS>_PROCESS_SRV/$metdata/ to backend
20xx-xx-xx xx:xx:xx,xxx +0200#INFO#com.sap.core.connectivity.protocol.http.handlers.HttpAuthorizationHandler#tunnel-client-516-3#0x817291d4#Access denied to http://<virtual-host>:443/<customer-service>-group.com/sap/opu/odata/sap/API_<CUSTOMER_PROCESS>_PROCESS_SRV/$metdata/ for virtual host <virtual-host>:443
20xx-xx-xx xx:xx:xx,xxx +0200#DEBUG#com.sap.core.connectivity.protocol.http.handlers.HttpRequestStateHandler#tunnel-client-516-3#0x817291d4#Http error occurred, switching state to FAILING
20xx-xx-xx xx:xx:xx,xxx +0200#DEBUG#com.sap.core.connectivity.spi.processing.OutboundConnectionErrorHandler#tunnel-client-516-3#0x817291d4#Protocol processing error:
com.sap.core.connectivity.protocol.http.handlers.HttpProtocolException: Access denied to resource http://<virtual-host>:443/<customer-service>-group.com/sap/opu/odata/sap/API_<CUSTOMER_PROCESS>_PROCESS_SRV/$metdata/ on system <virtual-host>:443. In case this was a valid request, ensure to expose the resource correctly in your cloud connector.
    at com.sap.core.connectivity.protocol.http.handlers.HttpAuthorizationHandler.handleHttpRequest(HttpAuthorizationHandler.java:81)
    at com.sap.core.connectivity.protocol.http.handlers.HttpAuthorizationHandler.writeImpl(HttpAuthorizationHandler.java:49)
    at com.sap.core.connectivity.protocol.http.handlers.AbstractHttpProtocolHandler.write(AbstractHttpProtocolHandler.java:91)
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• SAP Cloud Connector(SCC);
• SAP Business Technology Platform(BTP).

sap cloud connector, cc, connector, cloud connector, denied, resource denied, resource, HttpRequestStateHandler, HttpAuthorizationHandler, OutboundConnectionErrorHandler, expose, 403, forbidden , KBA , BC-MID-SCC , SAP Cloud Connector On-Demand/On-Premise Connectivity , Problem