Automatic mailing does not work for stand-alone products. Since it’s a manually created Product, it acts just like a standard WooCommerce product.
Automatic mailing makes use of the API which connects to your Suppliers server and automates the entire process from ordering to customer response.
The customer is automatically notified regarding their initial purchase, of course, regardless of the kind of product purchased.
For stand-alone products, further notifications to the customer are manually initiated, just like a standard WooCommerce product.
In the post How to Create a Stand-alone Unlock Product, it’s explained under the heading: “Updating the Stand-alone Unlock Product”
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3. Afterwards, you can enter the unlock code and/or instructions in the “Add note” section to the customer.
4. Make sure to change the note type to “Note to Customer” so that an email with details will be sent to the customer.
5. Click “Add” to add the custom message to this order
6. Click “Update” to save your changes and to notify the customer.
As the order passes through its various stages, the note sent to the customer can be whatever you like.
In Step 3 above, just replace “unlock code and/or instructions” with whatever update you’d like to send to the customer and follow the remaining steps to send the email containing any type of notification.
Since this is a stand-alone product and has no API connection to an external server (your Provider), how will the system “know” that the order was submitted or is available if it now relies upon you to actually submit and check its availability?
Only you will know this. Therefore, your customer relies on you to now manually update them.