A couple of things could be happening here, but I think the most likely issue is that you did not encode the URL of the video you're embedding.
I tested with both of your videos and was able to get successful responses like so:
https://vimeo.com/api/oembed.json?url=https%3a%2f%2fvimeo.com%2f392817533
and
https://vimeo.com/api/oembed.json?url=https%3a%2f%2fvimeo.com%2f360905947
Check out more from their documentation here:
Vimeo Developer Documentation
A noteworthy part of that page for others experiencing 404 errors is the "Handling errors" section where you'll see:
Http Status Code |
Probable cause |
404 |
You aren't able to access the video because of privacy or permissions issues, or because the video is still transcoding. |
This means the person who uploaded may have turned on a privacy setting which is blocking the oembed service from working. If possible, you could reach out to the owner and see if they are willing to update the video's privacy settings.