Hi,
It looks like your cloudflare firewall blocked you, based on this message: Cloudflare Ray ID: 86876f783b9977ae
WIthout knowing any details about the nature of the block, there is not much I can do except experiment maybe. The proper solution here is to access the firewall and deal with the false positive by whitelisting it. They could easily do that via the ray ID.
If you want, you can add temporary FTP details and I could try reverse removing fields one by one in the code to see which one may trigger the issue.