nginx .htpasswd

Hi,

I've a question. I have created a protected dir with a htpasswd file on server (centos 7, apache/nginx, plesk)

I want to protect the dir /cms and all what comes after that. Only when I login on /cms with user/pwd and go to /cms/dir or /cms/file.php, then often I get a second time I have to authenticate (not always). Is this a know issue? Is there something wrong with the config? Current config:

location ~ ^/cms/* {
auth_basic "something protected";
auth_basic_user_file /path/to/.htpasswd;
}

Hope anyone has an idea.

Kind regards,
Alex