Amazon Product not available for listing despite getting brand approval

Hi folks.
I am a new Amazon Reseller trying to use Amazon Fullfilment services.
Recently just applied to sell products of a particular brand and got the approval.
Thing is that, now we are sitting at 1400 units of a particular product of this brand, but, when we try to iniate the process to send it to FBO, it is just not available for listing:
What could it be? IS my account performance? My seller account is not new but I have only sold another type of product in the past. Could it be temporary limited due to Black Friday? Are there any work around this situation? I tried to contact Amazon and got this answer:
Your account does not currently meet the criteria required to list these products due to account metrics, distribution pathways of the brand, or other factors.
If your account becomes eligible to sell this product, you will see “Apply to sell” next to the product in the “Add Products” feature in Seller Central.
But how can I know which criteria is not met? What about other factors?
Any help would be appreciated.