Custom post types templates

If you are simply registering a custom post type called ‘services” then your register code should look like
register_post_type( ‘services’, $args );
Make sure the word “services” is exact in register_post_type. And
Your post_type word should be max. 20 characters, can not contain capital letters or spaces

Also make sure your has_archive parameter is set true like this
‘has_archive’ => true,

And don’t forget to flush the rewrite rule by clicking save in permalink setting in your backend after any change in the slug or permalink.Hope this helps you