The following two requirements need to be met for a successful integration with Amazon's API:
1. Professional Plan
The Seller Central account type must be upgraded to a 'Professional' selling plan.
Seller Central > Settings > Account Info
2. Admin Rights (User Permissions)
The user attempting the integration must have the necessary admin rights for your Seller Central account.
These rights may not always be sufficient though, see the exception mentioned further below.
Seller Central Settings > User Permissions > edit the user > grant rights to View & Edit User Permissions
Exceptions - Owner of Seller Central
In some cases it may be necessary to have the Seller Central account owner complete the integration. This is often the case when the user has only been given admin rights very recently.
In this case, you will need to ask your Seller Central owner to log in to your Sellics account and do the integration.
Sellics has no influence on the requirements made by Amazon for its API integration.
Select correct Marketplace in Sellics
Be sure to select the flag of the respective marketplace you'd like to connect to at the top right of the tool.
Ideal Browsers: Chrome & Firefox
Please also note that Sellics is mainly suited to Chrome and Firefox. Other browsers may cause various issues during the setup.