Installation error

[lambert.pierre]

Script URL:
Mods for HESK version: 2019.1.0
HESK version: 2.8.4
Hosting company: selfhost
URL of phpinfo.php:
URL of session_test.php:
What terms did you try when SEARCHING for a solution: installation, upgrade, MOD upgrade

Write your message below:

When i try to upgrade my existing HESK helpdesk i get the following error.

[lambert.pierre]

An error occurred! (Error Code: 14)
Could not execute query: ALTER TABLE `hesk_users` ADD COLUMN `notify_note_unassigned` ENUM('0', '1') NOT NULL DEFAULT '0'. MySQL said: Duplicate column name 'notify_note_unassigned'

An error occurred! (Error Code: 13)
Could not execute query: ALTER TABLE `hesk_users` DROP COLUMN `default_notify_customer_email`. MySQL said: Can't DROP COLUMN `default_notify_customer_email`; check that it exists