Freerouter doesn't want to route to inside an FPGA
Your traces might be too wide to fit between the pins without violating design rules. The vias are definitely too big.

Try routing that trace manually and see what happens. If you can't do it manually, the autorouter likely won't be able to either. If you can do it manually, then you can always just let the autorouter do as much as it can and clean up the rest manually.

It wouldn't be unusual to route a simple board like this entirely manually. I'd even say it would be best to do it manually if this is a first-time learning exercise. That way you can get a feel for how the process works and how all the rules work. After that you'll be better equipped to figure out what's going on when the autorouter fails.