error when I add a user or delete a multi-site site

Warning: Missing argument 2 for Appointments::remove_user_from_blog() in /home/secureth/public_html/wp-content/plugins/appointments/appointments.php on line 7081

Warning: Missing argument 2 for Appointments::remove_user_from_blog() in /home/secureth/public_html/wp-content/plugins/appointments/appointments.php on line 7081

Warning: Cannot modify header information – headers already sent by (output started at /home/secureth/public_html/wp-content/plugins/appointments/appointments.php:7081) in /home/secureth/public_html/wp-includes/pluggable.php on line 876