Redirection and duplicity of webpage

Hieverybody, I hope someone can help me.

I’ve beentrying to redirect my shop from the address smellsonice.co.uk to https://www.smellsonice.co.uk. because of the duplicity problem. After the .htaccess file has been configurated I’ve lost the access to the admin section ofZenCart and customers could not add the goods into the shopping baskets.

Could someone advise me how to sort out the duplicity issue and the configuration of the .htaccessfile while avoiding the above issue?

Thanks

You don't say what you've placed in your .htaccess file, but here's a copy of what's in mine that does the same thing. Note that I've got a bit in there so that my .htaccess works properly when I'm in my testing (i.e. localhost) environment, too:

# If the request comes in as smellsonice.co.uk, add the www. prefix
#
RewriteCond %{HTTP_HOST} !(^www\.smellsonice\.co\.uk$|^localhost$) [NC]
RewriteRule ^(.*)$ http://www.smellsonice.co.uk/$1 [R=301,L]

P.S. If you're really still on v1.3.7, you really, **really **need to upgrade!

Thanks for your answer.
I tried to add code to my .htaccess file. Redirection worked perfectly but after this change I was not able to add any products to my shopping cart. When I tried to add anything to shopping cart only inscription " Your shopping cart is empty." was appeared.

PK76:

Thanks for your answer.
I tried to add code to my .htaccess file. Redirection worked perfectly but after this change I was not able to add any products to my shopping cart. When I tried to add anything to shopping cart only inscription " Your shopping cart is empty." was appeared.
Make sure HTTP_SERVER and HTTPS_SERVER point to the new hostname. Otherwise you are causing extra 301s and may lose parameters from the requests.