Yes! This appears to be a simple peg count of particular lines. I don't see the need for anything complex. Maybe the Op can tell us if this works? Of course some tweaking of the regex'es...but looks like straight line code to me. I echo previous comments about "use strict; use warnings;".

while( my $line = <$log> ) 
{
  $Success_ArcotID_Count++ if ($line =~ /ArcotID\s*Auth\s*SUCCESS.*/);
  $Failure_ArcotID_Count++ if ($line =~ /Auth failed.*/);
  $Success_QnA_Count++ if ($line =~ /QNA Auth - Success.*/);
  $Failure_QnA_Count++ if ($line =~ /Message: QNA Auth Failed.*/);
  $Success_OTP_Count++ if ($line =~ /OTP SUCCESS.*/);
  $Failure_OTP_Count++ if ($line =~ /Message: OTP FAILED.*/);
  $Success_UP_Count++  if ($line =~ /UPAuth SUCCESS.*/);
  $Failure_UP_Count++  if ($line =~ /UPAuth FAILED.*/);
}
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If the above does indeed "work" in this application, it can be re-written so that token before either "SUCCESS" or "FAILED" creates a hash table peg count without needing this big "=0" declaration at the front.

I think others have covered the open ">$file" "clobbers previous $file" problem. If you want append, use ">>" for the open. Glob isn't portable, but that's a different subject. Get the basic stuff working and then we'll talk about that detail.