The oemebed endpoint for timeline embeds returns an error when using the parameter ‘widget_type=grid’
This was taken from the documentation found here: https://dev.twitter.com/web/embedded-timelines/oembed
Example URL: https://publish.twitter.com/oembed?url=https%3A%2F%2Ftwitter.com%2FTwitterDev%2Flists%2Fnational-parks&widget_type=grid
removing widget_type=grid results in a 200 response.
widget_type=grid only applies to collections. In your example you specified a list URL.
widget_type=grid
Thank you Niall, That was the information I needed.