Starting Sep 28, 2017 if you use the old versions of SQLBackupAndFTP v10 or lower and send backups to Dropbox, you will start getting error messages. The reason is that on that date Dropbox has stopped the support of API v1 and only newer versions of SQLBackupAndFTP support the new Dropbox API. More details here: https://sqlbackupandftp.com/blog/dropbox-has-stopped-the-support-of-api-v1