I'm running TM 5.7 on iOS 6.1.3 (iPhone 4). I get the error in the attached image every time I try to backup to Dropbox:
Error
The operation couldn't be completed. (NSURLErrorDomain error -1001.)
TM is properly logged in to Dropbox because it displays the correct Dropbox usage before I attempt the backup. Also, the simple reboot of the device doesn't affect this. It's been happening for a very long time, and I've rebooted many times with no change.
Thanks for your help.