True/False value issue in the Try Catch Block

the reason is though we have created a flag we have not let the process to get into CATCH block and usually a process in TRY block will go to CATCH block only when a exception is thrown
so THROW a exception with THROW activity
with these steps
Like in the same sequence mention above inside the IF condition, instead of SEND OUTLOOK MAIL ACTIVITY and BREAK activity use THROW activity
where create a business exception like this
New BusinessRuleException(“CUSTNAME column has a null valuee”)
so this will take use to CATCH block where we can have our SEND OUTLOOK MAIL ACTIVITY

kindly try this and let know for any queries or clarification
Cheers @balkishan