Remote and local backups failing or not running

[AaronW]

Hello. 

I have a bunch of CP 1550 and CP 3600/6200 that are set to run remote sftp backups to a server on our internal network over our SDWAN. The backup jobs were created and scheduled but don't always run, then again the local backups don't always run either.  The schedules were created fine after adding in the key for the server.  Sometimes I'll see the traffic hit the firewall logs, and it will show passing but sometimes I will get first packet isn't syn drops.  But for some of my firewalls despite the schedule it will not run the backups at all. 

When they run I don't see firewall drops due to rules, just syn not first drops.  But I'm also seeing firewalls just not run their scheduled backup jobs.   The Gaia are on R81.20 HF 119 and the embedded are on R81.10.17.

Is there any known bug that would cause this?  Also both are set for a max of 4 copies.  I'm assuming that is 4 for each backup schedule.  Do I need to manually delete old backup jobs or will it delete the oldest job when its at limit and a new backup runs?  But at the same time, I'm seeing gateways that have less than max backups still not run the local backup jobs.  

I can make a SSH connection from these to the Windows server that is hosting them, and a few of the clusters can backup without issues.  

Any tips on how to make this process work better?  I'm using the same config across all the units but some work fine, and other fail. 

What logs on the local hosts should I be checking for this?