Unable to Upload the File into DropBox From Salesforce Using /Files_put API ?

[Cross-linking for reference: https://stackoverflow.com/questions/36997863/unable-to-upload-the-file-into-dropbox-from-salesforce-using-files-put-api ]

I don't have any sample code for Apex specifically unfortunately.

I see you've updated your code to set the OAuth 2 access token. It looks like you're encoding it though? It shouldn't be encoded, and should just be passed up to the API as the original string.

By the way, I redacted your access token, but you should revoke it to be safe since you posted it publicly. 

Have you been able to troubleshoot the your code.HTTP client to check what data it is or isn't actually sending up?