Force a 403 response to xml file in WordPress

So to restate your question you want mydomain.com/autodiscover/autodiscover.xml to produce a 403, and your WordPress installation is at mydomain.com/ ?

Then this should do it to match that specific file only:

RewriteRule ^autodiscover/autodiscover.xml - [R=403,NC,L] 

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)