403 Directory access is forbidden

i am new in to this, i ftp all data it is under a directory, i have modified the .htacess file to

## Run InvoicePlane in a subfolder
## If you are using a subfolder please remove the hash in front of the line ‘#RewriteBase /subfolder’
## and replace ‘subfolder’ with the actual name of your folder, i.e. ‘RewriteBase /invoices’
<IfModule mod_rewrite.c>
  RewriteEngine On
  RewriteBase /
  RewriteRule ^index\.php$ - [L]
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteRule . /index.php [L]
  ## Remove the hash in front of the following two lines if you want to force HTTPS
  #RewriteCond %{HTTPS} off
  #RewriteRule ^(.*)$ https://%{HTTP_HOST}/$1 [R=301,L]

my directory name is invoice and i get this error 403 Directory access is forbidden.
how can i fix it???

You have to set the RewriteBase to RewriteBase /invoice