Trouble creating fillet on wheel spoke

Hello,

I'd like to create a fillet on the intersection shown circled in red just like the fillet that is circled in blue.

When I do everything the same way I did to create the fillet circled in bllue, I get a fillet that is rounded away from the hub, as shown.

When I try a face fillet, preview shows me what appears to be the fillet I want, but when I green-tick out, I get an error, as shown.

Any advice on what I might be doing wrong?

SolidworksParts And Features