I want to redirect mysite.com/index.php to  mysite.com/clientarea.php using .htaccess does not work for me help out.
with simple code.
I have tried several time and finally the site is not available  

Try running Windows Network Diagnostics.
  DNS_PROBE_FINISHED_NXDOMAIN
Based on that error, it appears you're redirecting to a different hostname than mysite.com - I assume unintentionally.  
If you can post your .htaccess code, the solution may be easy to provide.
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