Cannot move canonical url to permanently 301

[goodish]

I would like to change in the backoffice canonical url from temporarily  302. When is changed to permanently 301- page is white. Cache is cleared, new robot file...etc.

I tried to change through changes in htaccess: 

 

(RewriteCond %{HTTP_HOST} !^domain.com$
RewriteRule (.*) http://domain.com$1 [R=301,L]

 

- result the same.

 

Any idea?

 

Prestashop 1.6.0.14

Edited April 3, 2015 by goodish (see edit history)

[goodish]

SOLVED

 

Switched in the backoffice No redirection

 

Add to htaccess:

 

RewriteEngine on
Options +FollowSymLinks
RewriteCond %{THE_REQUEST} ^.*/index\.php
RewriteRule ^(.*)index.php$ http://www.mydomain.com/$1 [R=301,L]
RewriteCond %{HTTP_HOST} !^www\.mydomain\.com
RewriteRule (.*) http://www.mydomain.com/$1 [R=301,L]