Fatal error: Uncaught Error: call_user_func_array(): Argument #1 ($callback) must be a valid callback, function "domestika_excertp_length" not found or invalid function name
in /homepages/38/d236743738/htdocs/clickandbuilds/artene2/wp-includes/class-wp-hook.php on line 303

Call stack:

1. WP_Hook::apply_filters()
   wp-includes/plugin.php:189
2. apply_filters()
   wp-includes/formatting.php:3864
3. wp_trim_excerpt()
   wp-includes/class-wp-hook.php:303
4. WP_Hook::apply_filters()
   wp-includes/plugin.php:189
5. apply_filters()
   wp-includes/post-template.php:429
6. get_the_excerpt()
   wp-includes/feed.php:226
7. the_excerpt_rss()
   wp-includes/feed-rss2.php:103
8. require_once()
   wp-includes/template.php:770
9. load_template()
   wp-includes/functions.php:1623
10. do_feed_rss2()
    wp-includes/class-wp-hook.php:305
11. WP_Hook::apply_filters()
    wp-includes/class-wp-hook.php:327
12. WP_Hook::do_action()
    wp-includes/plugin.php:470
13. do_action()
    wp-includes/functions.php:1585
14. do_feed()
    wp-includes/template-loader.php:48
15. require_once()
    wp-blog-header.php:19
16. require()
    index.php:17