Error message

• Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/docroot/includes/common.inc:2861) in drupal_send_headers() (line 1554 of includes/bootstrap.inc).
• TypeError: count(): Argument #1 ($value) must be of type Countable|array, null given in count() (line 306 of sites/all/modules/custom/custom/ou_profile/profile_client/ou_profile_client.cron.inc).