A quick guide on problem orders.

In SelluSeller, an order falls under Problem orders state either due to:-

  1. Insufficient stock, i.e stock is 0.

  2. Unavailability of the SKU in SelluSeller. 
    This happens in case if the SKU/Product is directly created on Seller Center and if it has not been manually synced in SelluSeller.

Hope this answers your question.