Since it fails on that server but works otherwise, it sounds like there's something about that server setup that is preventing your code from successfully making the HTTPS connections to the Dropbox API servers. Is there anything on that network connection, such as a firewall, VPN, proxy, anti-virus, etc., that may be interfering with the connection to the Dropbox servers?
We can't offer support for your server or network connection itself, so you may need to refer to the documentation/support for that third party platform for help.
