Hello, @agenlebout

I hope this was sorted quickly on your end. I know it’s being a while since you’ve posted this, but I would like to share some useful information about the issue.

If you’re experiencing this issue from your droplet, e.g you’ve installed a Xfce desktop environment on your droplet:

https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-vnc-on-ubuntu-18-04

You can check if you’re able to reach other resources/sites without any issues and if the issue is only with reaching the host: dl.dropbox.com

If the you’re unable to reach other sites as well then you can check if the networking service on the droplet is working properly as you might experience some intermittent issues.

Also since this is Dropbox, you can check if they’re experiencing any issues at the moment as well. This will be the most likely reason for the issue that you’re experiencing.

Regards,
Alex