If you use different logins for your KDP & AMS accounts, you will need to connect the two. This is because Publishwide uses the Amazon KDP credentials you provided for all other Amazon platforms--AMS included.
Follow these instructions to connect your AMS and KDP accounts:
Step 1: Create a manager account.
Step 2: After you've created the manager account, click on the "Add an account" link
Step 3: Select the Request access tab
Step 4: Enter in the account ID for the AMS account you want to connect.
To find your account ID, log into the AMS account you want to connect
Copy everything in the URL after "EntityID="
Step 5: Approve the request by logging into the other AMS account and visiting this page
You have now connected your Amazon Advertising account to your Amazon KDP account and can resume syncing normally!
Questions? Issues? Feel free to reach out for assistance!