knowledgebase breaks site rewrites

[PDS]

My WHMCS is in a directory named support. I have the following in my public_html htaccess and the site is working without errors, everything is as expected:

 

Options +FollowSymlinks
RewriteEngine On
RewriteBase /

#Not show php ext
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^(.*)$ $1.php

#Change to the preferred domain
RewriteCond %{HTTP_HOST} ^www.domain.com$ [NC]
RewriteRule ^(.*)$ http://domain.com/$1 [R=301,L]

#Rewrite the URL for WHMCS to always use https except for the whmcs/dl.php file
RewriteCond %{REQUEST_URI} !^/support/dl.php [NC]
RewriteCond %{REQUEST_URI} ^/support/ [NC]
RewriteCond %{SERVER_PORT} !^443$
RewriteRule ^(.*)$ https://domain.com/$1 [R=301,L]

#Rewrite the URL for WHMCS dl area to always use http
RewriteCond %{REQUEST_URI} ^/support/dl.php [NC]
RewriteCond %{SERVER_PORT} !^80$
RewriteRule ^(.*)$ http://domain.com/$1 [R=301,L]

 

When I enable the below support directory htaccess to use KB it works but all rewrites fail, i.e I can use domain with WWW and navigate WHMCS using http and the WHMCS branding appears on the page.

 

# Knowledgebase
RewriteRule ^knowledgebase/([0-9]+)/[a-z0-9_-]+\.php$ knowledgebase.php?action=displayarticle&id=$1 [L,NC]
RewriteRule ^knowledgebase/([0-9]+)/([^/]*)$ knowledgebase.php?action=displaycat&catid=$1 [L,NC]
RewriteRule ^knowledgebase$ knowledgebase.php [L,NC]

 

I've asked support but they don't appear to know why. I've tried commenting out RewriteBase / and Options +FollowSymlinks but still same problem. SEF is ticked to use in admin

 

The server error log is:

 

Request exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary. Use 'LogLevel debug' to get a backtrace., referer: https://domain.com/support/knowledgebase.php

 

Which is an htaccess loop caused by adding the KB rule

 

Can anyone help me resolve this please?

[PDS]

Fixed having spent days on this.

 

The instructions I read said WHMCS rewrites have to be in web root. I've added them to the WHMCS subdirectory htaccess with knowledgebase, announcements and downloads directives and amended path. Works flawlessly now.