Remove filter from WordPress Plugin

I am using a plugin called that causes all of distributed posts to have a rel=canonical back to the source. I reached out to the developers and they told me the following:

By default, canonical URL of distributed post will point to original content, which corresponds to SEO best practices. This can be overridden by extending Distributor with custom code and removing Distributor’s default front end canonical URL filtering (look for ‘get_canonical_url’ and ‘wpseo_canonical’).

Here is their code:

public static function canonicalize_front_end() {
    add_filter( 'get_canonical_url', array( '\Distributor\InternalConnections\NetworkSiteConnection', 'canonical_url' ), 10, 2 );
    add_filter( 'wpseo_canonical', array( '\Distributor\InternalConnections\NetworkSiteConnection', 'wpseo_canonical_url' ) );
    add_filter( 'wpseo_opengraph_url', array( '\Distributor\InternalConnections\NetworkSiteConnection', 'wpseo_og_url' ) );
    add_filter( 'the_author', array( '\Distributor\InternalConnections\NetworkSiteConnection', 'the_author_distributed' ) );
    add_filter( 'author_link', array( '\Distributor\InternalConnections\NetworkSiteConnection', 'author_posts_url_distributed' ), 10, 3 );
}

I went into my child theme functions.php file and added the following:

  remove_filter( 'get_canonical_url', array( '\Distributor\InternalConnections\NetworkSiteConnection', 'canonical_url' ), 10, 2 );
  remove_filter( 'wpseo_canonical', array( '\Distributor\InternalConnections\NetworkSiteConnection', 'wpseo_canonical_url' ) );

It doesn’t seem to work for me. Any thoughts?

You can’t just add remove_filter() and have it remove the filters.

remove_filter() always has to happen after the callback you want to remove is added. Your remove_filter() call is most likely run before the plugin’s add_filter().

You need to find where/when that plugin hooks canonicalize_front_end() and then run your removal accordingly (i.e. at or after that).

For example, if canonicalize_front_end() is run at the init action, then you could do the following:

add_action( 'init', 'my_remove_filter' );
function my_remove_filter() {
    remove_filter( 'get_canonical_url', array( '\Distributor\InternalConnections\NetworkSiteConnection', 'canonical_url' ), 10, 2 );
    remove_filter( 'wpseo_canonical', array( '\Distributor\InternalConnections\NetworkSiteConnection', 'wpseo_canonical_url' ) );
}