'Authorization' header sent with request, but missing from apache_request_headers()

After some quick search found setting a rewrite rule works

 <IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
 </IfModule>

Can anyone tell me what it does ?

Yep..

RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]

or

SetEnvIf Authorization .+ HTTP_AUTHORIZATION=$0

..in .htaccess works for me..

I edited my .htaccess file as below. Then adding the last line solved the issue.

    RewriteEngine On 
    RewriteCond %{REQUEST_FILENAME} !-f 
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule ^(.*)$ %{ENV:BASE}index.php [QSA,L]
    SetEnvIf Authorization .+ HTTP_AUTHORIZATION=$0