The online racing simulator
HTTP Error 500 on a specific setup on lfs.net/files
Got interested a bit and decided to check setup list of that player. Here's handy link for you: https://www.lfs.net/files/setups/user/125244.
As you can see many setups of this player do not have any name next to them and also can't be downloaded. Among them there is a setup MandulAA is referencing - it's the first setup after you search "SO4R". Sets with names can be downloaded.
Here's example of player who shared setups and all of them are downloadable: https://www.lfs.net/files/setups/user/550896
** Best answer **
I've been looking into this .. I think at some point in January, (setup) attachments failed to be saved for a brief moment. Indeed a lot of setups of the user f!nal seemed to exhibit this problem. I'm removing these.

Because the above is an assumption and because I can't really find an obvious bug, I've added a bunch of debug messages in several places to monitor if / when this happens again.

FGED GREDG RDFGDR GSFDG