FTP always uses port 21. Just like HTTP (generally) uses port 80 and HTTPS (generally) uses port 443. There’s nothing you can do to change what port is used, because our FTP servers only listen on port 21.
Yesterday i called my provider and he told me that the url ftpupload.net is not reachable.
i got also an url-checker (URL Checker | Swisscom) and you can see that ftpupload is on a black list - i dont know why …
If Swisscom blocks ftpupload.net, then only Swisscom can say for certain why it’s blocked.
In any case, if you are using a “security” system that censors your internet access, then there is not much we can do about it. Perhaps you could try to appeal the block to Swisscom, as only they can get it removed. Or indeed use a VPN to bypass the block.