The IDOCs (both sent from the SAP to the Cloud and from the Cloud to the SAP) can be monitored with the standard SAP transactions. The mostly used transaction is WE02:
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Notice, that all IDOCs types which are relevant for FSM Cloud Connector start with /PACG*. Once you want to search for the IDOCs in the given Date/Time range this transaction is very useful. Double click the IDOC Number. The content of the IDOC is presented. By expanding the node "Data records" you can analyze the content of the IDOC:
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