Solved SFTP Backup Failing Randomly

[cparker_RCT]

I have a few self-hosted instances that have been backing up reliably to my FreeNAS that I have at my office since that feature was introduced in 3CX.
Recently, and intermittently I will have backups failing.

The email log indicates it's timing out while connecting.

If I am in the admin GUI, sometimes it times out connecting to my SFTP server and sometimes it connects instantly.
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More things to consider and mull over.
I recently built a new 3CX VM in Azure and I couldn't for the life of me get it to authenticate using SSH keys, even though my other VMs use keys just fine. However it works with password auth.

The other instances have been rebooted as a precaution to clear out any cobwebs and they're on the latest 3CX version.

I've just been banging my head on this as I don't recall making any changes on my side that would have affected this. It being intermittent is throwing me for a loop.

 

[ChrisC_3CX]

The fact that it times out, suggests a network/connectivity related issue. As a start, I'd recommend adjusting your scheduled backups as to ensure you do not have more than 1 3CX PBX performing a backup to the SFTP server at any given moment.

Regarding the issue with the SSH keys and Azure, I do not know what the reason could be. It may have to do with SSH configuration or maybe something Azure specific, I'd consult Azure's documentation or even contact their support if need be.

 

[cparker_RCT]

So, it is something dumb on my end. I implemented DNS filtering at the office where the backup target lives and for whatever reason that was interfering with the SSH/SFTP login process. Never seen that before, and it didn't impact it right away...

As soon as I removed it from the NAS, 3CX could authenticate quickly and reliably again.

 

[ChrisC_3CX]

Glad to hear you got this resolved! I'll be marking this thread as solved/closed but please do feel free to post a new one should you require additional information or assistance.