ERROR: Job has ended with errors in 2296 seconds

Hi,

Everyday I have the same message that I want to fix for my backup.

It’s :
[26-Oct-2015 03:27:49] 3. Try to send backup file to Dropbox …
[26-Oct-2015 03:27:50] Authenticated with Dropbox of user: XXXXX ([email protected])
[26-Oct-2015 03:27:50] 1 022,76 GB available on your Dropbox
[26-Oct-2015 03:27:50] Uploading to Dropbox …
[26-Oct-2015 03:44:12] WARNING: Job restarts due to inactivity for more than 5 minutes.

3 times and then :
[26-Oct-2015 03:44:12] ERROR: Step aborted: too many attempts!
[26-Oct-2015 03:44:12] ERROR: Job has ended with errors in 2296 seconds. You must resolve the errors for correct execution.

I search on forums and support :
-I have try to archive as any format
-Don’t backup cache and cache files
-Don’t backup the plugins, just the list

Nothing helps, I have the same message everyday. It’s a WP Multisite and I backup on Dropbox. No connection problem between the plugin and Dropbox, so I don’t understand.

Can you help me please ?

Thanks