What is “406-Not Acceptable Response” in HTTP?

Question

In my Ruby on Rails application I tried to upload an image through the POSTMAN REST client in Base64 format. When I POST the image I am getting a 406 Not Acceptable Resp

Answer 1

You can also receive a 406 response when invalid cookies are stored or referenced in the browser - for example, when running a Rails server in Dev mode locally.

If you happened to run two different projects on the same port, the browser might reference a cookie from a different localhost session.

This has happened to me...tripped me up for a minute. Looking in browser > Developer Mode > Network showed it.