Dear Tariz,
Use TC->SWEL to display Event Trace. Where digging in you will find what has gone wrong
Use tc ->SWIA to Execute work items if cannot track through agent
Use tc ->SWI1 to navigate to exact Work Item to see some thing is wrong
Use tc ->SWE2 to see if correct Event Type Linkages are being used
Check Reassigning SAP Work Items to a different User to see if it is problem with user access…right user...etc...Etc.
Thanks,
Kolusu