[ERROR] DropBox API: (503)

2012/10/30 23:16.22: [INFO]: BackWPup version 2.1.15, WordPress version 3.4.2 Copyright © 2012 Daniel Hüsken

2012/10/30 23:16.25: [INFO]: BackWPup job: 1. Daily; DB+FILE+OPTIMIZE+CHECK
2012/10/30 23:16.25: [INFO]: BackWPup cron: 5 23 * * *; Wed, 31 Oct 2012 @ 23:05
2012/10/30 23:16.25: [INFO]: BackWPup job started by cron
2012/10/30 23:16.25: [INFO]: PHP ver.: 5.2.17; cgi-fcgi; Linux
2012/10/30 23:16.25: [INFO]: MySQL ver.: 5.1.53-log
2012/10/30 23:16.25: [INFO]: curl ver.: 7.21.0; OpenSSL/0.9.8o

2012/10/30 23:31.32: 1. Try to sending backup file to DropBox…
2012/10/30 23:31.32: Authed with DropBox from website
2012/10/30 23:31.32: 1.26 GB free on DropBox
2012/10/30 23:31.32: Upload to DropBox now started…
2012/10/30 23:45.59: [ERROR] Job restarted, bcause inactivity!
2012/10/30 23:45.59: 2. Try to sending backup file to DropBox…
2012/10/30 23:46.01: [ERROR] DropBox API: (503) Your app is making too many requests and is being rate limited. 503s can trigger on a per-app or per-user basis.
2012/10/30 23:46.04: [ERROR] DropBox API: (503) Your app is making too many requests and is being rate limited. 503s can trigger on a per-app or per-user basis.
2012/10/30 23:46.04: 3. Try to sending backup file to DropBox…
2012/10/30 23:46.06: [ERROR] DropBox API: (503) Your app is making too many requests and is being rate limited. 503s can trigger on a per-app or per-user basis.
2012/10/30 23:46.08: [ERROR] DropBox API: (503) Your app is making too many requests and is being rate limited. 503s can trigger on a per-app or per-user basis.
2012/10/30 23:46.08: [ERROR] Step arborted has too many trys!

http://wordpress.org/extend/plugins/backwpup/