Warning: Cannot modify header information – Error message

Warning: Cannot modify header information – headers already sent by (output started at /…./…../public_html/…./…./wp-admin/includes/template.php:1877) in /…./…./public_html/…./…./wp-includes/pluggable.php on line 1178

I get the above error message when I attempt to change the settings and save.

https://wordpress.org/plugins/hide-plugin-updates-notifications/