Hi Yanfen,
Go to transaction ST01 and select "Authorization Check" under Trace Components and click on "Trace On."
Ask the user to execute the transaction.
Once the user either complets the transaction or encounters the error message, go back to St01 and click on "Trace Off"
Then, click on "Analysis"
Replace the User name with the userid of the user who executed the transaction and select the appropriate range of dates and then click on the execute button.
This will show you all the authorization checks that was encountered by the user.
You will get details.
Thanks and regards,
Mohit Gohil