This may represent an issue with your advertising API credentials.
I have provided some details on it below - including a workaround provided by Amazon:
- Amazon PPC uses two API connections from Amazon -- "MWS API" and "Advertising API". (Both are required by PPC Scope due to some of the advanced features offered.)
- MWS API uses your seller marketplace domains such as .com, .co.uk, etc.
- Advertising API only works with .com marketplace for authentication, regardless of which marketplace you are selling on.
- The first step in PPCScope authorization is to connect MWS API.
- The second step is the Advertising API authorization.
If you use a single login (email address) in Seller Central for all your marketplaces-- there is a known bug within Amazon's Advertising API connection process that may prevent properly connecting for all accounts:
- In order to get around this issue, Amazon recommends you create a separate guest user account in Seller Central for each of marketplace not connecting that will be used to re-authenticate in PPC Scope for the marketplace:
- Once the above guest user account is created, login to your PPCScope account, then navigate to Settings -> Account Settings > Amazon Accounts
- On the Amazon Accounts tab, click on 'Connect Sponsored Ads API' orange link for each EU marketplace being added and authorized.
- When redirected to the .com domain on Amazon's side use the new users created in workaround step 1 above for each of the respective accounts.