You must determine your desired organization billing date (day of the month your invoices and finalized and become due) before you start using Optix. This field is by default the 1st of the month, and can only be edited until such time that invoices are created in Optix.
To determine if your billing date has been locked:
Select Settings from the left-hand menu
Click Features then Invoicing
If you see a greyed out bar under 'Billing date of the month' your billing date is indeed locked, otherwise you will be able to edit this field.
For further support with invoice billing dates, please contact firstname.lastname@example.org
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