This error means that the credentials you created the Bol.com connection in Channable with don't give us access to your Bol.com account to send your products there. Please follow the steps below to fix this.
Step 1 - Check your Bol.com connection in Channable
Go to the "Settings" of your Bol.com marketplace in Channable and click on the Bol connection. The correct Bol connection will appear automatically.
In the next screen you'll find the public and private key with which you've created your Bol.com connection.
Step 2 - Check your settings in your Bol.com account
Now go to the settings of your Bol.com seller account (follow this link) and click "instellingen":
In the next screen, at the bottom you will see a switch for "Ik wil mijn oude API keys inzien". Make sure it is switched to "Ja".
After activating the switch, scroll until you see the "API keys voor productie", make sure you ignore the "API keys voor test".
Step 3 - create a new connection if necessary
Now compare the "API keys voor productie" with the API keys in your Channable connection (see step 1). If they are different you should create a new connection in Channable and use the API keys that you've found in step 2. Create a new marketplace that uses the new connection with the right API keys, and we should be able to start sending your products to Bol.com.
You can create a new connection in Channable by going to APIs and clicking the blue "+ Add new API" button. That will take you to a screen comparable to the screen below.
Add a new Bol.com connection and make sure you use the API keys from step 2!