SQLBak to Dropbox backup - transport connection error

[arkroyal]

I use SQLBak to backup several MS SQL Server DBs to an internal NAS device and then copy the backups to a shared Dropbox folder for disaster recovery purposes. Seven days ago, ALL of my SQLBak backup jobs to Dropbox started failing with the error message below. I have already raised a ticket with SQLBak and they confirmed that it does not appear to be an issue with the SQLBak agent and suggested that a change to Dropbox may have caused it. Anyone got any ideas?

[DST-4:1103#2] Failed to upload "C:\Windows\TEMP\SqlBakTestFile.bak" file to "gollum" folder. > One or more errors occurred. > An error occurred while sending the request. > The underlying connection was closed: An unexpected error occurred on a send. > Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. > An existing connection was forcibly closed by the remote host

[Rich]

The solution is to get an updated version of the SQLBak app, if available, so that it supports the latest Dropbox API. You'll have to contact the developer, though it sounds like they may have abadoned it (at least as of six months ago).

[arkroyal]

Finally found a solution last week. Not SQLBak-related, but a Dropbox API-related URL was being blocked by our firewall. Add the following URL to your firewall's allowed domains list:

dropbox-api.arkoselabs.com

This must have been a change affected by Dropbox, because our SQLBak replicated backups to Dropbox were working fine up to a point. I was also experiencing problems with the Dropbox Business client on a workstation. Solved when allowing the above URL.

Hope it fixes your problem.

[JohnnyTq]

Could you give more details about unblocking in firewall ? I created new inbound and outbound rules with the IP found pinging this URL but nothing changed  .

[arkroyal]

No changes were made to inbound/outbound rules on Windows firewall. I added the URL to our perimeter SonicWall appliance's allowed domain list.