There are a couple of reason why products are not appearing for your influencers to select from in their Live URLs. The first reason could be that the products have not been added as compensation within your campaign details.
The second reason that can cause your products not to appear for selection in your influencers Live URLs is leaving the inventory quantity at 0. If you enable the inventory tracking, but leave the quantity at 0, the products will not appear as an option for your influencers.
To adjust the inventory quantity, go into the "Brands" tab and click on the basket icon.
Then, click on the pencil icon to make changes to a product and adjust the inventory quantity in the "Product Inventory" step.
To learn more about proposals, click here.