A reminder was not sent

The usual reasons.

Reminders are off: Settings → Notifications → Automatic reminders.
The partner has no email, or the yacht has no owner email: the reminder is skipped (shown as "no email" in Run now).
The instalment is paid, or not due yet according to your "days before" setting.
The daily run happens at the send time you chose (Greece time).
The account is in read-only mode.
It failed: Settings → Notifications → Sent reminders shows the error.

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