Error message when activating inbound port in Aif: "There is already a listener on IP endpoint"

Solution :  Stop AOS.
Delete the files under XPPIL directory located under Server BIN directory.
Truncate table (SysXPPAssembly) from SQL.
Restart the AOS.
Basically the IL binary files which are saved in this table might have been messed up there! On the AOS restart it produces the binaries freshly and updates the table which should fix the issue.