Specifying the Authentication Method for the Connection 
You have to change the authentication method for the connection to authentication assertion tickets.
In the SAP NetWeaver Administrator of the consumer system, navigate to
In the destination tree, select the entry that corresponds to the ActionInboxConnectorWS of the provider system. You can identify the entry by the alias of the provider system you have defined in the previous steps.
Example
sap.com/tc~kmc~km.appl.ui~aibproxy/com.sap.netweaver.bc.uwl.core.connect.wsaib.proxy.ActionInboxConnectorWSProxy/<Provider_ALIAS>
In the Authentication dropdown list, choose Assertion Ticket.
Save your entries.