@Simran2 ,
As per your Workflow out of 10 Emails even if 1 Email contains required Subject it will not go to else part and throw the exception.
Out of N Emails even if 1 contains invalid and if u need to throw exception in this case you need to reverse the condition in 1st If - Else block.
Assign Boolean = True in else block (which means Invalid Email found)
In 2nd If - Else block if your Boolean is true throw exception.
This way it will throw exception even if 1 Invalid found.
But not sure what is your need here, this suggestion is based on your workflow.
Hope it helps!
Regards,
Rohith