Dear Friends: Thanks for taking patience in answering the question. I have the issue resolved like this but I am not sure how it works. Here is the code

my $subject="Monthly Report";

my $file_link="\n Dear Customer: Please click on the link below to dow
+nload the Monthly Report for the month of 2019-05. <br><br> <a href=\
+"https://$hostname/ui_report/download_report?file=$fileloc\">Download
+ Report</a></center> \n\n"; # $fileloc contains the path of the store
+d file in our server.

&SendEmail($from,$toAddress,$cc,$bcc,$subject,'text/html',$file_link,$
+from); # This module sends an email with link - by clicking will down
+load the excel report.



In the "download_report" script:

if ($file =~ /\.xlsx$/) {
    
print "Content-type: application/vnd.openxmlformats-officedocument.spr
+eadsheetml.sheet\n";
# The Content-Disposition will generate a prompt to save the file.
print "Content-Disposition: attachment; filename=$file\n";
print "\n";
&download ($fileloc);
exit 0; # NEWLY ADDED DUE TO ISSUE IN EXCEL REPORT OPENING
} 

print "Content-Type: text/html\r\n\r\n";
 my $cgi = new CGI;
 print $cgi->redirect("tent");
 print "The redirect seems to have failed.";
 die;
[download]

By simply adding "exit 0; " statement I am able to download and view the report without any warnings. I believe previously after the execution of if block, it continued the execution and it might have created the problem. Please let me know if my explanation is not sufficient.