Issue:

This error typically arises if you are enrolled in the Remote Fulfillment with FBA program (also known as NARF) and some or all of your products are listed as sellable through FBA.

Error Message : "An FBA offer already exists on this SKU. To create a seller fulfilled SKU, either create a new SKU or make the SwitchFulfillmentTo value MFN."

Resolution:

This error typically arises if you are enrolled in the Remote Fulfillment with FBA program (also known as NARF) and some or all of your products are listed as sellable through FBA.

Option 1: Ensure Separate SKUs

Always use distinct SKUs when selling the same item on Amazon MFN and FBA

Option 2: Opt-Out of the Remote Fulfillment Program

If you do not intend to use the Remote Fulfillment program or have accidentally enrolled in it, opting out will resolve the issue. To opt-out:

Option 3: Adjust Affected SKUs

If only a few SKUs are inadvertently affected, you can work with Amazon to remove those specific SKUs from the FBA program. Alternatively, separating the FBA and MFN products into two distinct listings on Amazon should also fix the issue.