Uncaught Error: CoAuthors_Plus::filter_author_archive_title(): Return value must be of type string, null returned
in /var/www/html/wp-content/mu-plugins/co-authors-plus/php/class-coauthors-plus.php on line 1892

Call stack:

1. CoAuthors_Plus::filter_author_archive_title(NULL)
   wp-includes/class-wp-hook.php:343
2. WP_Hook::apply_filters(NULL, array)
   wp-includes/plugin.php:205
3. apply_filters('get_the_archive_title', NULL, NULL, false)
   wp-includes/general-template.php:1809
4. get_the_archive_title()
   wp-content/plugins/ms-metrics/includes/services/oneds.php:262
5. Microsoft\Metrics\OneDS\get_awa_page_type()
   wp-content/plugins/ms-metrics/includes/services/oneds.php:93
6. Microsoft\Metrics\OneDS\include_awa_meta('')
   wp-includes/class-wp-hook.php:341
7. WP_Hook::apply_filters(NULL, array)
   wp-includes/class-wp-hook.php:365
8. WP_Hook::do_action(array)
   wp-includes/plugin.php:522
9. do_action('wp_head')
   wp-includes/general-template.php:3197
10. wp_head()
    wp-includes/template-canvas.php:17
11. include('/var/www/html/wp-includes/template-canvas.php')
    wp-includes/template-loader.php:132
12. require_once('/var/www/html/wp-includes/template-loader.php')
    wp-blog-header.php:19
13. require('/var/www/html/wp-blog-header.php')
    index.php:17