Page template defaulting to index.php

I have a custom post type registered but don’t want to use the archive page for it. I instead want to use a page template and just run WP_Query on it. On my localhost this works 100% but when uploading to a live server for some reason when I go to the page I set up it defaults to index.php instead of using my template page. Is there a reason for this?

The page I created is called ‘galleries’ and as mentioned I use WP_Query to get the records from the ‘portfolio’ custom post type. I did this so that I could still use the Gutenberg editor on the page and put some content before showing the post type info.