Currently the gallery url – yourwebsite.com/gallery is reserved for theme gallery page .
First you need to change the theme gallery slug to something else.
In plugins/livemesh-tools/includes/register-post-types.php search for the below line of code and change it
'rewrite' => array('slug' => 'gallery'),
to
'rewrite' => array('slug' => 'our-gallery'),
You will need to visit Settings->Permalinks once for the slug change to take effect.
And now you can create a gallery page named “Gallery” of your own .