Hi Darryl!
I just had a peek at your store and that error has seemingly disappeared. Did you figure out what the problem was or did it resolve itself?
In my experience the "unknown can't be blank" error arises under the following circumstances:
- When the store has a multi-user Google Merchant Centre account - this can be resolved by adding the account IDs for the sub-accounts associated with this store to the Google Shopping app.
https://support.google.com/merchants/answer/1637190?hl=en - When Google modifies the labels for the product fields - this can be resolved by letting us know so we can update our labels accordingly.
Let us know if that doesn't cover your case, Darryl, and I'll be happy to investigate further :)
Cheers!
Genevieve S.