Hey there Angelique!
Genevieve from Shopify here :)
From looking at your store, it seems that all the 'Unknown missing' errors relate to missing GTIN or MPN entries.
You can learn more about these from Google at the below resources:
https://support.google.com/merchants/answer/160161
https://support.google.com/merchants/answer/188494?hl=en
If you populate these fields and find that the error persists, please do let me know : )
Hope that helps!
Genevieve S.