Cerber is blocking Updraft Plus plugin

Hello,

Cerber is blocking Updraft Plus plugin when attempting to setup a backup to a DropBox account.

https://www.my-domain.com/wp-admin/options-general.php?page=updraftplus&action=updraftmethod-dropbox-auth (it is supposed to connect to Dropbox in order to get an authorization to access my account)

same when directly typing my custom admin url : https://www.my-domain.com/my-custom-admin-url/options-general.php?page=updraftplus&action=updraftmethod-dropbox-auth

Despite whitelisting the query ?page=updraftplus&action=updraftmethod-dropbox-auth
I get a 403 “We’re sorry, you are not allowed to proceed” message.

ANY idea how to allow external access to this plugin ?