Prestashop API errors
Option 1 : Prestashop services aren't enabled
Sometimes those settings aren't set to properly so prestashop won't authorize a 3rd party to connect to their servers.
Go to your Prestashop into "advanced settings" -> "Webservice" and make sure both options are set on "Yes".
The CGI option isn't mandatory if your server isn't compatible.
Option 2 : API key's permissions aren't set
After creating a new API key in prestashop, you need to make sure it has all the permissions so that ChannelDock can access everything.
In order to do that, go to "advanced settings" -> "webservice" and select the API key you used in ChannelDock. Then tick all the boxes in the permissions and press save.
Option 3 : HTaccess authorisation
Sometimes Prestashop isn't set up to allow web services to connect to the API. To fix that you need to make sure that your HTaccess contains this instruction :
SetEnvIf Authorization "(.*)" HTTP_AUTHORIZATION=$1