When you have settlements showing with an "unknown" marketplace it means that the settlements in question are ones where we can't detect the marketplace.
Amazon settlements don't actually tell us which marketplace they came from so we have to look inside the settlement report to see if there are any transactions which have the marketplace showing.
Usually there are as any sale, most fees and lots of other transaction types show the marketplace, but there are a few that don't.
Settlements showing as "select marketplace" don't have any lines that contain the marketplace info and therefore they fail to process.
This means that those settlements don't contain any sales or other transactions that allow us to identify the marketplace.
We have a fix for this whereby you as the user manually check which marketplace these settlements are form inside seller central and then select the correct marketplace on your dashboard on Link My Books.
Effected settlements will show a "Select Marketplace" button instead of the marketplace name. All you need to do is:
Check in Seller Central which marketplace the settlement is from using the amount.
Click the Select Marketplace button for the settlement on the dashboard in Link My Books.
Select the correct marketplace from the dropdown.
In Amazon Seller Central you will need to switch between the different Amazon marketplaces using the marketplace selector at the top of Seller Central.
Then navigate to the Reports > Payments page.
On that page navigate to the All Statements tab.
Then look to see if the settlement amount showing in Link My Books is showing in the list of settlements from that marketplace.
If not then switch to another marketplace and try again. Eventually you will find the marketplace that settlement came from and you can then select it on the dashboard in Link My Books.
This will then allow us to process these settlements to your accounts & tax rate preferences.