The watsonplatform.net endpoint URL is retired. Update your code to use the specific watson.cloud.ibm.com URL for your service.
I am getting the above error in my facebook chat bot.
I have created new API service credentials as per this link
https://cloud.ibm.com/docs/watson?topic=watson-endpoint-change
and added it to ibm cloud.
https://website.region.mybluemix.net/
getting 404 for this.
Where should the newly created api endpoint be updated for facebook chat bot to work ?