Enable access to your Amazon PPC account, go to tool4seller and click the Access Amazon MWS button on the PPC Optimization.
In this window, click the Connect button to complete your advertising token authorization.
What should you do if you encounter an authorization failure? Please follow the hints display in a pop-up window.
If you still can not complete the authorization after check-in for the above reasons, you can try to grant the right of advertising to a brand new sub-seller account and repeat authorization.
How to assign permissions to sub-seller account (Click the linck below):
More questions, welcome to contact us at firstname.lastname@example.org.