Error message

• Warning: Cannot modify header information - headers already sent by (output started at /usr/local/share/drupal-7.67/includes/common.inc:2791) in drupal_send_headers() (line 1499 of /usr/local/share/drupal-7.67/includes/bootstrap.inc).
• TypeError: Argument 1 passed to xmlsitemap_node_create_link() must be an instance of stdClass, boolean given, called in /home/members/timesup/sites/times-up.org/web/sites/all/modules/contrib/xmlsitemap/xmlsitemap_node/xmlsitemap_node.module on line 28 in xmlsitemap_node_create_link() (line 194 of /home/members/timesup/sites/times-up.org/web/sites/all/modules/contrib/xmlsitemap/xmlsitemap_node/xmlsitemap_node.module).