text after blog post

Hi there, my developer is running into problems with shortening the amount of text that is displayed on the blog post previews. I would like it to be 3 lines and it is showing much more than that. He asked me to pass along that he tried 2 plugins:

-advanced-excerpt
-easy-custom-auto-excerpt

Also added the following code to child theme:

function custom_excerpt_length( $length ) {
return 20;
}
add_filter( ‘excerpt_length’, ‘custom_excerpt_length’, 999 );

Also edited WP core file

-the above methods did not work. I will post the link in a follow up post.

Ticket