I can log in to Egnyte with my creds, but my bearer token request gives a 403
I'd like to get started with the Egnyte API. I have an account and a key, but when I POST to /puboauth/token, I get a 403 error with the detail "Invalid username and/or password or account is locked." These creds (copied and pasted) work just fine for logging in to Egnyte. The only thing I see which could confuse the matter is that my username is my e-mail address, and therefore it contains an ampersand; I have tried URL encoding it, but I get the same error message.
Here's the exact body, as reported by Fiddler, changed only to hide the credentials:
Can anyone see a reason this request shouldn't work?
The Support guy who informed me that my API key was registered suggested I use a different user name, which does not match what I use to log into Egnyte nor developers.egnyte.com, but that did not work any better.