PowerEdge R515 Platform Update

Hello, I'm aware that this server isn't supported anymore, but are there still any catalogs for this model to update? If so, how do I connect to it? I've tried connecting through ftp.dell.com and that just says Network Error. I've also tried downloads.dell.com and that one says 'Downloading Catalog' and then says Network Error.

Maybe I've just got it configured wrong but when I click Test Network Connection it says everything passes.

I don't know much about this stuff, so I could be going about this the wrong way.

Any help is appreciated.